Recording multiple spatially-heterodyned direct to digital holograms in one digital image

DOEpatents

Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN

2008-03-25

Systems and methods are described for recording multiple spatially-heterodyned direct to digital holograms in one digital image. A method includes digitally recording, at a first reference beam-object beam angle, a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram to sit on top of a first spatial-heterodyne carrier frequency defined by the first reference beam-object beam angle; digitally recording, at a second reference beam-object beam angle, a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram to sit on top of a second spatial-heterodyne carrier frequency defined by the second reference beam-object beam angle; applying a first digital filter to cut off signals around the first original origin and define a first result; performing a first inverse Fourier transform on the first result; applying a second digital filter to cut off signals around the second original origin and define a second result; and performing a second inverse Fourier transform on the second result, wherein the first reference beam-object beam angle is not equal to the second reference beam-object beam angle and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

Spatially-Heterodyned Holography

DOEpatents

Thomas, Clarence E [Knoxville, TN; Hanson, Gregory R [Clinton, TN

2006-02-21

A method of recording a spatially low-frequency heterodyne hologram, including spatially heterodyne fringes for Fourier analysis, includes: splitting a laser beam into a reference beam and an object beam; interacting the object beam with an object; focusing the reference beam and the object beam at a focal plane of a digital recorder to form a spatially low-frequency heterodyne hologram including spatially heterodyne fringes for Fourier analysis; digital recording the spatially low-frequency heterodyne hologram; Fourier transforming axes of the recorded spatially low-frequency heterodyne hologram including spatially heterodyne fringes in Fourier space to sit on top of a heterodyne carrier frequency defined by an angle between the reference beam and the object beam; cutting off signals around an origin; and performing an inverse Fourier transform.

A Dual Frequency Carrier Phase Error Difference Checking Algorithm for the GNSS Compass.

PubMed

Liu, Shuo; Zhang, Lei; Li, Jian

2016-11-24

The performance of the Global Navigation Satellite System (GNSS) compass is related to the quality of carrier phase measurement. How to process the carrier phase error properly is important to improve the GNSS compass accuracy. In this work, we propose a dual frequency carrier phase error difference checking algorithm for the GNSS compass. The algorithm aims at eliminating large carrier phase error in dual frequency double differenced carrier phase measurement according to the error difference between two frequencies. The advantage of the proposed algorithm is that it does not need additional environment information and has a good performance on multiple large errors compared with previous research. The core of the proposed algorithm is removing the geographical distance from the dual frequency carrier phase measurement, then the carrier phase error is separated and detectable. We generate the Double Differenced Geometry-Free (DDGF) measurement according to the characteristic that the different frequency carrier phase measurements contain the same geometrical distance. Then, we propose the DDGF detection to detect the large carrier phase error difference between two frequencies. The theoretical performance of the proposed DDGF detection is analyzed. An open sky test, a manmade multipath test and an urban vehicle test were carried out to evaluate the performance of the proposed algorithm. The result shows that the proposed DDGF detection is able to detect large error in dual frequency carrier phase measurement by checking the error difference between two frequencies. After the DDGF detection, the accuracy of the baseline vector is improved in the GNSS compass.

Responsible implementation of expanded carrier screening

PubMed Central

Henneman, Lidewij; Borry, Pascal; Chokoshvili, Davit; Cornel, Martina C; van El, Carla G; Forzano, Francesca; Hall, Alison; Howard, Heidi C; Janssens, Sandra; Kayserili, Hülya; Lakeman, Phillis; Lucassen, Anneke; Metcalfe, Sylvia A; Vidmar, Lovro; de Wert, Guido; Dondorp, Wybo J; Peterlin, Borut

2016-01-01

This document of the European Society of Human Genetics contains recommendations regarding responsible implementation of expanded carrier screening. Carrier screening is defined here as the detection of carrier status of recessive diseases in couples or persons who do not have an a priori increased risk of being a carrier based on their or their partners' personal or family history. Expanded carrier screening offers carrier screening for multiple autosomal and X-linked recessive disorders, facilitated by new genetic testing technologies, and allows testing of individuals regardless of ancestry or geographic origin. Carrier screening aims to identify couples who have an increased risk of having an affected child in order to facilitate informed reproductive decision making. In previous decades, carrier screening was typically performed for one or few relatively common recessive disorders associated with significant morbidity, reduced life-expectancy and often because of a considerable higher carrier frequency in a specific population for certain diseases. New genetic testing technologies enable the expansion of screening to multiple conditions, genes or sequence variants. Expanded carrier screening panels that have been introduced to date have been advertised and offered to health care professionals and the public on a commercial basis. This document discusses the challenges that expanded carrier screening might pose in the context of the lessons learnt from decades of population-based carrier screening and in the context of existing screening criteria. It aims to contribute to the public and professional discussion and to arrive at better clinical and laboratory practice guidelines. PMID:26980105

140 GHz pulsed Fourier transform microwave spectrometer

DOEpatents

Kolbe, W.F.; Leskovar, B.

1985-07-29

A high frequency energy pulsing system suitable for use in a pulsed microwave spectrometer, including means for generating a high frequency carrier signal, and means for generating a low frequency modulating signal. The carrier signal is continuously fed to a modulator and the modulating signal is fed through a pulse switch to the modulator. When the pulse switch is on, the modulator will produce sideband signals above and below the carrier signal frequency. A frequency-responsive device is tuned to one of the sideband signals and sway from the carrier frequency so that the high frequency energization of the frequency-responsive device is controlled by the pulse switch.

140 GHz pulsed Fourier transform microwave spectrometer

DOEpatents

Kolbe, W.F.; Leskovar, B.

1987-10-27

A high frequency energy pulsing system suitable for use in a pulsed microwave spectrometer, including means for generating a high frequency carrier signal, and means for generating a low frequency modulating signal is disclosed. The carrier signal is continuously fed to a modulator and the modulating signal is fed through a pulse switch to the modulator. When the pulse switch is on, the modulator will produce sideband signals above and below the carrier signal frequency. A frequency-responsive device is tuned to one of the sideband signals and away from the carrier frequency so that the high frequency energization of the frequency-responsive device is controlled by the pulse switch. 5 figs.

Encoding frequency contrast in primate auditory cortex

PubMed Central

Scott, Brian H.; Semple, Malcolm N.

2014-01-01

Changes in amplitude and frequency jointly determine much of the communicative significance of complex acoustic signals, including human speech. We have previously described responses of neurons in the core auditory cortex of awake rhesus macaques to sinusoidal amplitude modulation (SAM) signals. Here we report a complementary study of sinusoidal frequency modulation (SFM) in the same neurons. Responses to SFM were analogous to SAM responses in that changes in multiple parameters defining SFM stimuli (e.g., modulation frequency, modulation depth, carrier frequency) were robustly encoded in the temporal dynamics of the spike trains. For example, changes in the carrier frequency produced highly reproducible changes in shapes of the modulation period histogram, consistent with the notion that the instantaneous probability of discharge mirrors the moment-by-moment spectrum at low modulation rates. The upper limit for phase locking was similar across SAM and SFM within neurons, suggesting shared biophysical constraints on temporal processing. Using spike train classification methods, we found that neural thresholds for modulation depth discrimination are typically far lower than would be predicted from frequency tuning to static tones. This “dynamic hyperacuity” suggests a substantial central enhancement of the neural representation of frequency changes relative to the auditory periphery. Spike timing information was superior to average rate information when discriminating among SFM signals, and even when discriminating among static tones varying in frequency. This finding held even when differences in total spike count across stimuli were normalized, indicating both the primacy and generality of temporal response dynamics in cortical auditory processing. PMID:24598525

140 GHz pulsed fourier transform microwave spectrometer

DOEpatents

Kolbe, William F.; Leskovar, Branko

1987-01-01

A high frequency energy pulsing system suitable for use in a pulsed microwave spectrometer (10), including means (11, 19) for generating a high frequency carrier signal, and means (12) for generating a low frequency modulating signal. The carrier signal is continuously fed to a modulator (20) and the modulating signal is fed through a pulse switch (23) to the modulator. When the pulse switch (23) is on, the modulator (20) will produce sideband signals above and below the carrier signal frequency. A frequency-responsive device (31) is tuned to one of the sideband signals and away from the carrier frequency so that the high frequency energization of the frequency-responsive device (31) is controlled by the pulse switch (23).

Characteristics of Electromagnetic Pulse Propagation in Metal

NASA Technical Reports Server (NTRS)

Namkung, M.; Wincheski, B.; Nath, S.; Fulton, J. P.

2004-01-01

It is well known that the solution of the diffusion equation for an electromagnetic field with a time harmonic term, e(sup iwt), is in the form of a traveling wave whose amplitude attenuates over distance into a conducting medium. As the attenuation is an increasing function of frequency, the high frequency components attenuate more rapidly than those of low ones upon entering a well conducting object. At the same time, the phase velocity of an individual component is also an increasing function of frequency causing a broadening of the pulse traveling inside a conductor. In the results of our previous study of numerical simulations, the problem of using a gaussian input pulse was immediately clear. First, having the dominant frequency components distributed around zero, the movement of the peak was not well defined. Second, with the amplitude of fourier components varying slowly over a wide range, the dispersion-induced blurring of the peak position was seen to be severe. For the present study, we have used a gaussian modulated single frequency sinusoidal wave, i. e., the carrier, as an input pulse in an effort to improve the issues related to the unclear movement of peak and dispersion as described above. This was based on the following two anticipated advantages: First, the packet moves in a conductor at the group velocity calculated at the carrier frequency, which means it is well controllable. Second, the amplitude of frequency components other than that of the carrier can be almost negligible, such that the effect of dispersion can be significantly reduced. A series of experiments of transmitting electromagnetic pulses through aluminum plates of various thickness was performed to test the validity of the above points. The results of numerical simulation based on wave propagation are discussed with respect to the experimental results. Finally, a simple simulation was performed based on diffusion of a continuous sine wave input and the results are compared with those of a single frequency sinusoidal wave observed over time at difference locations inside a conductor.

Performance Analysis of Control Signal Transmission Technique for Cognitive Radios in Dynamic Spectrum Access Networks

NASA Astrophysics Data System (ADS)

Sakata, Ren; Tomioka, Tazuko; Kobayashi, Takahiro

When cognitive radio (CR) systems dynamically use the frequency band, a control signal is necessary to indicate which carrier frequencies are currently available in the network. In order to keep efficient spectrum utilization, this control signal also should be transmitted based on the channel conditions. If transmitters dynamically select carrier frequencies, receivers have to receive control signals without knowledge of their carrier frequencies. To enable such transmission and reception, this paper proposes a novel scheme called DCPT (Differential Code Parallel Transmission). With DCPT, receivers can receive low-rate information with no knowledge of the carrier frequencies. The transmitter transmits two signals whose carrier frequencies are spaced by a predefined value. The absolute values of the carrier frequencies can be varied. When the receiver acquires the DCPT signal, it multiplies the signal by a frequency-shifted version of the signal; this yields a DC component that represents the data signal which is then demodulated. The performance was evaluated by means of numerical analysis and computer simulation. We confirmed that DCPT operates successfully even under severe interference if its parameters are appropriately configured.

ACE Gene I/D Polymorphism and Obesity in 1,574 Patients with Type 2 Diabetes Mellitus.

PubMed

Pan, Yan-Hong; Wang, Min; Huang, Yan-Mei; Wang, Ying-Hui; Chen, Yin-Ling; Geng, Li-Jun; Zhang, Xiao-Xi; Zhao, Hai-Lu

2016-01-01

Association between ACE gene I/D polymorphism and the risk of overweight/obesity remains controversial. We investigated the possible relationship between ACE gene I/D polymorphism and obesity in Chinese type 2 diabetes mellitus (T2DM) patients. In this study, obesity was defined as a body mass index (BMI) value ≥ 25 kg/m 2 and subjects were classified into 4 groups (lean, normal, overweight, and obese). PCR (polymerase chain reaction) was used to detect the ACE gene I/D polymorphism in T2DM patients. Metabolic measurements including blood glucose, lipid profile, and blood pressure were obtained. Frequencies of the ACE genotypes (DD, ID, and II) were not significant among the 4 groups of BMI-defined patients ( P = 0.679) while ACE II carriers showed higher systolic blood pressure (SBP) and pulse pressure (PP) (all P < 0.050). Hyperglycemia, hypertension, and dyslipidemia in these T2DM patients were found to be significantly associated with BMI. In conclusion, the relationship of ACE gene I/D polymorphism with obesity is insignificant in Chinese patients with T2DM. SBP and PP might be higher in the ACE II carriers than in the DD and ID carriers.

Taenia solium Cysticercosis Hotspots Surrounding Tapeworm Carriers: Clustering on Human Seroprevalence but Not on Seizures

PubMed Central

Lescano, Andres G.; Garcia, Hector H.; Gilman, Robert H.; Gavidia, Cesar M.; Tsang, Victor C. W.; Rodriguez, Silvia; Moulton, Lawrence H.; Villaran, Manuel V.; Montano, Silvia M.; Gonzalez, Armando E.

2009-01-01

Background Neurocysticercosis accounts for 30%–50% of all late-onset epilepsy in endemic countries. We assessed the clustering patterns of Taenia solium human cysticercosis seropositivity and seizures around tapeworm carriers in seven rural communities in Peru. Methodology The presence of T. solium–specific antibodies was defined as one or more positive bands in the enzyme-linked immunoelectrotransfer blot (EITB). Neurocysticercosis-related seizures cases were diagnosed clinically and had positive neuroimaging or EITB. Principal Findings Eleven tapeworm carriers were identified by stool microscopy. The seroprevalence of human cysticercosis was 24% (196/803). Seroprevalence was 21% >50 m from a carrier and increased to 32% at 1–50 m (p = 0.047), and from that distance seroprevalence had another significant increase to 64% at the homes of carriers (p = 0.004). Seizure prevalence was 3.0% (25/837) but there were no differences between any pair of distance ranges (p = 0.629, Wald test 2 degrees of freedom). Conclusion/Significance We observed a significant human cysticercosis seroprevalence gradient surrounding current tapeworm carriers, although cysticercosis-related seizures did not cluster around carriers. Due to differences in the timing of the two outcomes, seroprevalence may reflect recent T. solium exposure more accurately than seizure frequency. PMID:19172178

Continued investigation of potential application of Omega navigation to civil aviation

NASA Technical Reports Server (NTRS)

Baxa, E. G., Jr.

1978-01-01

Major attention is given to an analysis of receiver repeatability in measuring OMEGA phase data. Repeatability is defined as the ability of two like receivers which are co-located to achieve the same LOP phase readings. Specific data analysis is presented. A propagation model is described which has been used in the analysis of propagation anomalies. Composite OMEGA analysis is presented in terms of carrier phase correlation analysis and the determination of carrier phase weighting coefficients for minimizing composite phase variation. Differential OMEGA error analysis is presented for receiver separations. Three frequency analysis includes LOP error and position error based on three and four OMEGA transmissions. Results of phase amplitude correlation studies are presented.

Risk of Japanese carriers of hyperphosphorylated paratarg-7, the first autosomal-dominantly inherited risk factor for hematological neoplasms, to develop monoclonal gammopathy of undetermined significance and multiple myeloma.

PubMed

Grass, Sandra; Iida, Shinsuke; Wikowicz, Aleksandra; Preuss, Klaus-Dieter; Inagaki, Atsushi; Shimizu, Kazuyuki; Ziepert, Marita; Ueda, Ryuzo; Pfreundschuh, Michael

2011-03-01

Hyperphosphorylated paratarg-7 (pP-7) is a frequent target of paraproteins in German patients with monoclonal gammopathy of undetermined significance (MGUS)/multiple myeloma (MM). The frequency of MGUS/MM is lower in Japan than in Europe. As pP-7, the first molecularly defined autosomal-dominant risk factor for any hematological neoplasm, is inherited in a dominant fashion, we determined the incidence of the pP-7 carrier state in a Japanese population, and compared the frequency of pP-7-specific paraproteins and the pP-7 carrier state in Japanese and German patients with MGUS/MM. Peripheral blood from 111 Japanese patients with MGUS/MM and 278 healthy blood donors was analyzed for the pP-7 carrier state by isoelectric focusing and for pP-7-specific antibodies by ELISA. The Japanese group was compared with 252 German MGUS/MM patients and 200 healthy controls. Five of 111 (4.5%) Japanese and 35/252 (13.9%) German IgA/IgG MGUS/MM patients had a pP-7-specific paraprotein (P=0.009). The prevalence of healthy pP-7 carriers in the Japanese study group was 1/278 (0.36%), whereas it was 4/200 in the German group (P=0.166). The relative risk for pP-7 carriers developing MGUS/MM had an odds ratio of 13.1 in the Japanese and 7.9 in the German group. In conclusion, the fraction of pP-7 carriers with a pP-7-specific paraprotein is lower among Japanese than in German patients with MGUS/MM, but pP-7 carriers in both ethnic groups have a high risk of developing MGUS/MM. © 2011 Japanese Cancer Association.

Architecture and settings optimization procedure of a TES frequency domain multiplexed readout firmware

NASA Astrophysics Data System (ADS)

Clenet, A.; Ravera, L.; Bertrand, B.; den Hartog, R.; Jackson, B.; van Leeuwen, B.-J.; van Loon, D.; Parot, Y.; Pointecouteau, E.; Sournac, A.

2014-11-01

IRAP is developing the readout electronics of the SPICA-SAFARI's TES bolometer arrays. Based on the frequency domain multiplexing technique the readout electronics provides the AC-signals to voltage-bias the detectors; it demodulates the data; and it computes a feedback to linearize the detection chain. The feedback is computed with a specific technique, so called baseband feedback (BBFB) which ensures that the loop is stable even with long propagation and processing delays (i.e. several μ s) and with fast signals (i.e. frequency carriers of the order of 5 MHz). To optimize the power consumption we took advantage of the reduced science signal bandwidth to decouple the signal sampling frequency and the data processing rate. This technique allowed a reduction of the power consumption of the circuit by a factor of 10. Beyond the firmware architecture the optimization of the instrument concerns the characterization routines and the definition of the optimal parameters. Indeed, to operate an array TES one has to properly define about 21000 parameters. We defined a set of procedures to automatically characterize these parameters and find out the optimal settings.

Multipactor susceptibility on a dielectric with two carrier frequencies

NASA Astrophysics Data System (ADS)

Iqbal, Asif; Verboncoeur, John; Zhang, Peng

2018-04-01

This work investigates multipactor discharge on a single dielectric surface with two carrier frequencies of an rf electric field. We use Monte Carlo simulations and analytical calculations to obtain susceptibility diagrams in terms of the rf electric field and normal electric field due to the residual charge on the dielectric. It is found that in contrast to the single frequency case, in general, the presence of a second carrier frequency of the rf electric field increases the threshold of the magnitude of the rf electric field to initiate multipactor. The effects of the relative strength and phase, and the frequency separation of the two carrier frequencies are examined. The conditions to minimize mulitpactor are derived.

Carrier-frequency synchronization system for improved amplitude modulation and television broadcast reception

DOEpatents

Smith, Stephen F.; Moore, James A.

2003-05-13

Systems and methods are described for carrier-frequency synchronization for improved AM and TV broadcast reception. A method includes synchronizing a carrier frequency of a broadcast signal with a remote reference frequency. An apparatus includes a reference signal receiver; a phase comparator coupled to the reference signal receiver; a voltage controlled oscillator coupled to the phase comparator; and a radio frequency output coupled to the voltage controlled oscillator.

47 CFR 78.111 - Frequency tolerance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES CABLE TELEVISION RELAY... shall maintain their operating frequency within 0.0005% the visual carrier, and the aural carrier shall be 4.5 MHz ±1 kHz above the visual carrier frequency. [52 FR 7145, Mar. 9, 1987, as amended at 68 FR...

Digital EPR with an arbitrary waveform generator and direct detection at the carrier frequency

PubMed Central

Tseitlin, Mark; Quine, Richard W.; Rinard, George A.; Eaton, Sandra S.; Eaton, Gareth R.

2011-01-01

A digital EPR spectrometer was constructed by replacing the traditional bridge with an arbitrary waveform generator (AWG) to produce excitation patterns and a high-speed digitizer for direct detection of the spin system response at the carrier frequency. Digital down-conversion produced baseband signals in quadrature with very precise orthogonality. Real-time resonator tuning was performed by monitoring the Fourier transforms of signals reflected from the resonator during frequency sweeps generated by the AWG. The capabilities of the system were demonstrated by rapid magnetic field scans at 256 MHz carrier frequency, and FID and spin echo experiments at 1 and 10 GHz carrier frequencies. For the rapid scan experiments the leakage through a cross-loop resonator was compensated by adjusting the amplitude and phase of a sinusoid at the carrier frequency that was generated with another AWG channel. PMID:21968420

Artifactual responses when recording auditory steady-state responses.

PubMed

Small, Susan A; Stapells, David R

2004-12-01

The goal of this study was to investigate, in hearing-impaired participants who could not hear the stimuli, the possibility of artifactual auditory steady-state responses (ASSRs) when stimuli are presented at high intensities. ASSRs to single (60 dB HL) and multiple (20 to 50 dB HL; 500 to 4000 Hz) bone-conduction stimuli as well as single 114 to 120 dB HL air-conduction stimuli, were obtained using the Rotman MASTER system, using analog-to-digital (A/D) conversion rates of 500, 1000, and 1250 Hz. Responses (p < 0.05) were considered artifactual when their numbers exceeded that expected by chance. In some conditions, we also obtained ASSRs to "alternated" stimuli (stimuli inverted and ASSRs to the two polarities averaged). A total of 17 subjects were tested. Bone conduction results: 500 Hz A/D rate: Large-amplitude (43 to 1558 nV) artifactual ASSRs were seen at 40 and 50 dB HL for the 500 Hz carrier frequency. Smaller responses (28 to 53 nV) were also recorded at 20 dB HL for the 500 Hz carrier frequency. Artifactual ASSRs (17 to 62 nV) were seen at 40 dB HL and above for the 1000 Hz carrier frequency and at 50 dB HL for the 2000 Hz carrier frequency. Alternating the stimulus polarity decreased the amplitude and occurrence of these artifactual responses but did not eliminate responses for the 500 Hz carrier frequency at 40 dB HL and above. No artifactual responses were recorded for 4000 Hz stimuli for any condition. 1000 Hz A/D rate: Artifactual ASSRs (15 to 523 nV) were seen at 50 dB HL and above for the 500 Hz carrier frequency and 40 dB HL and above for the 1000 Hz carrier frequency. Artifactual responses were also obtained at 50 dB HL for a 2000 Hz carrier frequency but not at lower levels. Artifactual responses were not seen for the 4000 Hz carrier frequency. Alternating the stimulus polarity removed the responses for the 1000 and 2000 Hz carrier frequencies but did not change the results for the 500 Hz carrier frequency. 1250 Hz A/D rate: Artifactual ASSRs (16 to 220 nV) were seen at 50 dB HL and above for the 500 Hz carrier frequency and 60 dB HL and above for the 1000 Hz carrier frequency. Alternating the stimulus polarity removed the responses for the 1000 Hz carrier frequency but did not change the results for the 500 Hz carrier frequency. There were no artifactual responses at 2000 and 4000 Hz. Air conduction results: 500 Hz A/D rate: Artifactual ASSRs (49 to 153 nV) were seen for 114 to 120 dB HL stimuli for 500 and 1000 Hz carrier frequencies. Alternating the stimulus polarity removed these responses. There were no artifactual responses at 2000 and 4000 Hz. 1000 and 1250 Hz A/D rates: Artifactual ASSRs (19 to 55 nV) were seen for a 120 dB HL stimulus for a 1000 Hz carrier. Alternating the stimulus polarity removed these responses. High-intensity air- or bone-conduction stimuli can produce spurious ASSRs, especially for 500 and 1000 Hz carrier frequencies. High-amplitude stimulus artifact can result in energy that is aliased to exactly the modulation frequency. Choice of signal conditioning (electroencephalogram filter slope and low-pass cutoff) and processing (A/D rate) can avoid spurious responses due to aliasing. However, artifactual responses due to other causes may still occur for bone-conduction stimuli 50 dB HL and higher (and possibly for high-level air conduction). Because the phases of these spurious responses do not invert with inversion of stimulus, the possibility of nonauditory physiologic responses cannot be ruled out. The clinical implications of these results are that artifactual responses may occur for any patient for bone-conduction stimuli at levels greater than 40 dB HL and for high-intensity air-conduction stimuli used to assess patients with profound hearing loss.

Experience with Carrier Screening and Prenatal Diagnosis for Sixteen Ashkenazi Jewish Genetic Diseases

PubMed Central

Scott, Stuart A.; Edelmann, Lisa; Liu, Liu; Luo, Minjie; Desnick, Robert J.; Kornreich, Ruth

2010-01-01

The success of prenatal carrier screening as a disease prevention strategy in the Ashkenazi Jewish (AJ) population has driven the expansion of screening panels as disease-causing founder mutations have been identified. However, the carrier frequencies of many of these mutations have not been reported in large AJ cohorts. We determined the carrier frequencies of over 100 mutations for 16 recessive disorders in the New York metropolitan area AJ population. Among the 100% AJ-descended individuals, screening for 16 disorders resulted in ~1 in 3.3 being a carrier for one disease and ~1 in 24 for two diseases. The carrier frequencies ranged from 0.066 (1 in 15.2; Gaucher disease) to 0.006 (1 in 168; nemaline myopathy), which averaged ~15% higher than those for all screenees. Importantly, over 95% of screenees chose to be screened for all possible AJ diseases, including disorders with lower carrier frequencies and/or detectability. Carrier screening also identified rare individuals homozygous for disease-causing mutations who had previously unrecognized clinical manifestations. Additionally, prenatal testing results and experience for all 16 disorders (n = 574) are reported. Together, these data indicate the general acceptance, carrier frequencies, and prenatal testing results for an expanded panel of 16 diseases in the AJ population. PMID:20672374

Software Configurable Multichannel Transceiver

NASA Technical Reports Server (NTRS)

Freudinger, Lawrence C.; Cornelius, Harold; Hickling, Ron; Brooks, Walter

2009-01-01

Emerging test instrumentation and test scenarios increasingly require network communication to manage complexity. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. A fundamental requirement for a software-definable radio system is independence from carrier frequencies, one of the radio components that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate the viability of a promising chipset that performs conversion of radio frequency (RF) signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit the size of a commodity disk drive, programmable for any frequency band between 1 MHz and 6 GHz.

14 CFR 205.2 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-01-01

... air carriers, including commuter air carriers and air taxi operators as defined in § 298.2 of this chapter, and foreign direct air carriers, including Canadian charter air taxi operators as defined in...

14 CFR 205.2 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... air carriers, including commuter air carriers and air taxi operators as defined in § 298.2 of this chapter, and foreign direct air carriers, including Canadian charter air taxi operators as defined in...

Range Sidelobe Suppression Using Complementary Sets in Distributed Multistatic Radar Networks

PubMed Central

Wang, Xuezhi; Song, Yongping; Huang, Xiaotao; Moran, Bill

2017-01-01

We propose an alternative waveform scheme built on mutually-orthogonal complementary sets for a distributed multistatic radar. Our analysis and simulation show a reduced frequency band requirement for signal separation between antennas with centralized signal processing using the same carrier frequency. While the scheme can tolerate fluctuations of carrier frequencies and phases, range sidelobes arise when carrier frequencies between antennas are significantly different. PMID:29295566

Spatial-heterodyne interferometry for transmission (SHIFT) measurements

DOEpatents

Bingham, Philip R.; Hanson, Gregory R.; Tobin, Ken W.

2006-10-10

Systems and methods are described for spatial-heterodyne interferometry for transmission (SHIFT) measurements. A method includes digitally recording a spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis using a reference beam, and an object beam that is transmitted through an object that is at least partially translucent; Fourier analyzing the digitally recorded spatially-heterodyned hologram, by shifting an original origin of the digitally recorded spatially-heterodyned hologram to sit on top of a spatial-heterodyne carrier frequency defined by an angle between the reference beam and the object beam, to define an analyzed image; digitally filtering the analyzed image to cut off signals around the original origin to define a result; and performing an inverse Fourier transform on the result.

Ultrasonic speech translator and communications system

DOEpatents

Akerman, M.A.; Ayers, C.W.; Haynes, H.D.

1996-07-23

A wireless communication system undetectable by radio frequency methods for converting audio signals, including human voice, to electronic signals in the ultrasonic frequency range, transmitting the ultrasonic signal by way of acoustical pressure waves across a carrier medium, including gases, liquids, or solids, and reconverting the ultrasonic acoustical pressure waves back to the original audio signal. The ultrasonic speech translator and communication system includes an ultrasonic transmitting device and an ultrasonic receiving device. The ultrasonic transmitting device accepts as input an audio signal such as human voice input from a microphone or tape deck. The ultrasonic transmitting device frequency modulates an ultrasonic carrier signal with the audio signal producing a frequency modulated ultrasonic carrier signal, which is transmitted via acoustical pressure waves across a carrier medium such as gases, liquids or solids. The ultrasonic receiving device converts the frequency modulated ultrasonic acoustical pressure waves to a frequency modulated electronic signal, demodulates the audio signal from the ultrasonic carrier signal, and conditions the demodulated audio signal to reproduce the original audio signal at its output. 7 figs.

Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

DOEpatents

Pitel, Ira J.

1987-02-03

The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

DOEpatents

Pitel, I.J.

1987-02-03

The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

High-frequency homogenization for travelling waves in periodic media.

PubMed

Harutyunyan, Davit; Milton, Graeme W; Craster, Richard V

2016-07-01

We consider high-frequency homogenization in periodic media for travelling waves of several different equations: the wave equation for scalar-valued waves such as acoustics; the wave equation for vector-valued waves such as electromagnetism and elasticity; and a system that encompasses the Schrödinger equation. This homogenization applies when the wavelength is of the order of the size of the medium periodicity cell. The travelling wave is assumed to be the sum of two waves: a modulated Bloch carrier wave having crystal wavevector [Formula: see text] and frequency ω 1 plus a modulated Bloch carrier wave having crystal wavevector [Formula: see text] and frequency ω 2 . We derive effective equations for the modulating functions, and then prove that there is no coupling in the effective equations between the two different waves both in the scalar and the system cases. To be precise, we prove that there is no coupling unless ω 1 = ω 2 and [Formula: see text] where Λ =(λ 1 λ 2 …λ d ) is the periodicity cell of the medium and for any two vectors [Formula: see text] the product a ⊙ b is defined to be the vector ( a 1 b 1 , a 2 b 2 ,…, a d b d ). This last condition forces the carrier waves to be equivalent Bloch waves meaning that the coupling constants in the system of effective equations vanish. We use two-scale analysis and some new weak-convergence type lemmas. The analysis is not at the same level of rigour as that of Allaire and co-workers who use two-scale convergence theory to treat the problem, but has the advantage of simplicity which will allow it to be easily extended to the case where there is degeneracy of the Bloch eigenvalue.

Amplitude modulation detection with concurrent frequency modulation.

PubMed

Nagaraj, Naveen K

2016-09-01

Human speech consists of concomitant temporal modulations in amplitude and frequency that are crucial for speech perception. In this study, amplitude modulation (AM) detection thresholds were measured for 550 and 5000 Hz carriers with and without concurrent frequency modulation (FM), at AM rates crucial for speech perception. Results indicate that adding 40 Hz FM interferes with AM detection, more so for 5000 Hz carrier and for frequency deviations exceeding the critical bandwidth of the carrier frequency. These findings suggest that future cochlear implant processors, encoding speech fine-structures may consider limiting the FM to narrow bandwidth and to low frequencies.

Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis

PubMed

Jones; Diddams; Ranka; Stentz; Windeler; Hall; Cundiff

2000-04-28

We stabilized the carrier-envelope phase of the pulses emitted by a femtosecond mode-locked laser by using the powerful tools of frequency-domain laser stabilization. We confirmed control of the pulse-to-pulse carrier-envelope phase using temporal cross correlation. This phase stabilization locks the absolute frequencies emitted by the laser, which we used to perform absolute optical frequency measurements that were directly referenced to a stable microwave clock.

Measurement of the carrier envelope offset frequency of a femtosecond frequency comb using a Fabry-Perot interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basnak, D V; Bikmukhametov, K A; Dmitrieva, N I

2010-10-15

A method for measuring the carrier envelope offset (CEO) frequency of the femtosecond frequency comb with a bandwidth of less than one octave by using a Fabry-Perot interferometer is proposed and experimentally demonstrated. (laser components)

The E23K and A190A variations of the KCNJ11 gene are associated with early-onset type 2 diabetes and blood pressure in the Chinese population.

PubMed

Zhuang, Langen; Zhao, Yu; Zhao, Weijing; Li, Ming; Yu, Ming; Lu, Ming; Zhang, Rong; Ge, Xiaoxu; Zheng, Taishan; Li, Can; Yin, Jun; Yin, Jingyuan; Bao, Yuqian; Liu, Limei; Jia, Weiping; Liu, Yanjun

2015-06-01

Conflicting associations between define (KCNJ11) variations and susceptibility to late-onset (>40 years old) type 2 diabetes mellitus (T2DM) have been reported in different ethnic groups. We investigated whether the E23K (G→A, rs5219) or A190A (C→T, rs5218) variations in KCNJ11 are associated with early-onset T2DM and blood pressure in the Chinese population. Case-control study of 175 unrelated Chinese patients with early-onset T2DM (age of onset <40 years old) who receive (ins+, n = 57) or do not receive insulin (ins-, n = 118), and 182 non-diabetic control subjects. PCR-direct sequencing was performed to genotype E23K and A190A; the genotypic frequencies and associations with clinical characteristics were analyzed. The genotypic frequencies of E23K-GA+AA were higher and A190A-TT was lower in the early-onset T2DM group, especially the T2D-ins+ group, compared to the non-diabetic control group (p < 0.01 or 0.05, respectively). In non-diabetic subjects, E23K-AA carriers had significantly higher 2 h plasma glucose and lower 2 h insulin than E23K-GG carriers (both p < 0.05). A190A-TT or E23K-GG carriers had higher systolic blood pressure (SBP) than CC or AA carriers in the non-diabetic control and T2DM groups (both p < 0.05). In the T2DM ins+ group, E23K-AA carriers had lower onset age and duration of diabetes and higher BMI than GG carriers, and A190A-TT carriers had higher SBP than CC carriers (all p < 0.05). The E23K-GA or AA genotypes may increase the susceptibility to early-onset T2DM, while A190A-TT may protect against early-onset T2DM. On the other hand the A190A-TT or E23K-GG genotypes may increase the risk of hypertension in the Chinese population.

Notched-noise precursors improve detection of low-frequency amplitude modulationa)

PubMed Central

Almishaal, Ali; Bidelman, Gavin M.; Jennings, Skyler G.

2017-01-01

Amplitude modulation (AM) detection was measured with a short (50 ms), high-frequency carrier as a function of carrier level (Experiment I) and modulation frequency (Experiment II) for conditions with or without a notched-noise precursor. A longer carrier (500 ms) was also included in Experiment I. When the carrier was preceded by silence (no precursor condition) AM detection thresholds worsened for moderate-level carriers compared to lower- or higher-level carriers, resulting in a “mid-level hump.” AM detection thresholds with a precursor were better than those without a precursor, primarily for moderate-to-high level carriers, thus eliminating the mid-level hump in AM detection. When the carrier was 500 ms, AM thresholds improved by a constant (across all levels) relative to AM thresholds with a precursor, consistent with the longer carrier providing more “looks” to detect the AM signal. Experiment II revealed that improved AM detection with compared to without a precursor is limited to low-modulation frequencies (<60 Hz). These results are consistent with (1) a reduction in cochlear gain over the course of the precursor perhaps via the medial olivocochlear reflex or (2) a form of perceptual enhancement which may be mediated by adaptation of inhibition. PMID:28147582

The DCU: the detector control unit for SPICA-SAFARI

NASA Astrophysics Data System (ADS)

Clénet, Antoine; Ravera, Laurent; Bertrand, Bernard; den Hartog, Roland H.; Jackson, Brian D.; van Leeuven, Bert-Joost; van Loon, Dennis; Parot, Yann; Pointecouteau, Etienne; Sournac, Anthony

2014-08-01

IRAP is developing the warm electronic, so called Detector Control Unit" (DCU), in charge of the readout of the SPICA-SAFARI's TES type detectors. The architecture of the electronics used to readout the 3 500 sensors of the 3 focal plane arrays is based on the frequency domain multiplexing technique (FDM). In each of the 24 detection channels the data of up to 160 pixels are multiplexed in frequency domain between 1 and 3:3 MHz. The DCU provides the AC signals to voltage-bias the detectors; it demodulates the detectors data which are readout in the cold by a SQUID; and it computes a feedback signal for the SQUID to linearize the detection chain in order to optimize its dynamic range. The feedback is computed with a specific technique, so called baseband feedback (BBFB) which ensures that the loop is stable even with long propagation and processing delays (i.e. several µs) and with fast signals (i.e. frequency carriers at 3:3 MHz). This digital signal processing is complex and has to be done at the same time for the 3 500 pixels. It thus requires an optimisation of the power consumption. We took the advantage of the relatively reduced science signal bandwidth (i.e. 20 - 40 Hz) to decouple the signal sampling frequency (10 MHz) and the data processing rate. Thanks to this method we managed to reduce the total number of operations per second and thus the power consumption of the digital processing circuit by a factor of 10. Moreover we used time multiplexing techniques to share the resources of the circuit (e.g. a single BBFB module processes 32 pixels). The current version of the firmware is under validation in a Xilinx Virtex 5 FPGA, the final version will be developed in a space qualified digital ASIC. Beyond the firmware architecture the optimization of the instrument concerns the characterization routines and the definition of the optimal parameters. Indeed the operation of the detection and readout chains requires to properly define more than 17 500 parameters (about 5 parameters per pixel). Thus it is mandatory to work out an automatic procedure to set up these optimal values. We defined a fast algorithm which characterizes the phase correction to be applied by the BBFB firmware and the pixel resonance frequencies. We also defined a technique to define the AC-carrier initial phases in such a way that the amplitude of their sum is minimized (for a better use of the DAC dynamic range).

Ultrasonic speech translator and communications system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akerman, M.A.; Ayers, C.W.; Haynes, H.D.

1996-07-23

A wireless communication system undetectable by radio frequency methods for converting audio signals, including human voice, to electronic signals in the ultrasonic frequency range, transmitting the ultrasonic signal by way of acoustical pressure waves across a carrier medium, including gases, liquids, or solids, and reconverting the ultrasonic acoustical pressure waves back to the original audio signal. The ultrasonic speech translator and communication system includes an ultrasonic transmitting device and an ultrasonic receiving device. The ultrasonic transmitting device accepts as input an audio signal such as human voice input from a microphone or tape deck. The ultrasonic transmitting device frequency modulatesmore » an ultrasonic carrier signal with the audio signal producing a frequency modulated ultrasonic carrier signal, which is transmitted via acoustical pressure waves across a carrier medium such as gases, liquids or solids. The ultrasonic receiving device converts the frequency modulated ultrasonic acoustical pressure waves to a frequency modulated electronic signal, demodulates the audio signal from the ultrasonic carrier signal, and conditions the demodulated audio signal to reproduce the original audio signal at its output. 7 figs.« less

Ultrasonic speech translator and communications system

DOEpatents

Akerman, M. Alfred; Ayers, Curtis W.; Haynes, Howard D.

1996-01-01

A wireless communication system undetectable by radio frequency methods for converting audio signals, including human voice, to electronic signals in the ultrasonic frequency range, transmitting the ultrasonic signal by way of acoustical pressure waves across a carrier medium, including gases, liquids, or solids, and reconverting the ultrasonic acoustical pressure waves back to the original audio signal. The ultrasonic speech translator and communication system (20) includes an ultrasonic transmitting device (100) and an ultrasonic receiving device (200). The ultrasonic transmitting device (100) accepts as input (115) an audio signal such as human voice input from a microphone (114) or tape deck. The ultrasonic transmitting device (100) frequency modulates an ultrasonic carrier signal with the audio signal producing a frequency modulated ultrasonic carrier signal, which is transmitted via acoustical pressure waves across a carrier medium such as gases, liquids or solids. The ultrasonic receiving device (200) converts the frequency modulated ultrasonic acoustical pressure waves to a frequency modulated electronic signal, demodulates the audio signal from the ultrasonic carrier signal, and conditions the demodulated audio signal to reproduce the original audio signal at its output (250).

A time-frequency classifier for human gait recognition

NASA Astrophysics Data System (ADS)

Mobasseri, Bijan G.; Amin, Moeness G.

2009-05-01

Radar has established itself as an effective all-weather, day or night sensor. Radar signals can penetrate walls and provide information on moving targets. Recently, radar has been used as an effective biometric sensor for classification of gait. The return from a coherent radar system contains a frequency offset in the carrier frequency, known as the Doppler Effect. The movements of arms and legs give rise to micro Doppler which can be clearly detailed in the time-frequency domain using traditional or modern time-frequency signal representation. In this paper we propose a gait classifier based on subspace learning using principal components analysis(PCA). The training set consists of feature vectors defined as either time or frequency snapshots taken from the spectrogram of radar backscatter. We show that gait signature is captured effectively in feature vectors. Feature vectors are then used in training a minimum distance classifier based on Mahalanobis distance metric. Results show that gait classification with high accuracy and short observation window is achievable using the proposed classifier.

47 CFR 76.1804 - Aeronautical frequencies: leakage monitoring (CLI).

Code of Federal Regulations, 2010 CFR

2010-10-01

... through 76.616 and § 76.1803; (d) Carrier frequency, tolerance, and type of modulation of all carriers in... 47 Telecommunication 4 2010-10-01 2010-10-01 false Aeronautical frequencies: leakage monitoring... Aeronautical frequencies: leakage monitoring (CLI). An MVPD shall notify the Commission before transmitting any...

Al{sub 70}Pd{sub 21.5}Mn{sub 8.5}: A quasicrystal showing the de haas-van Alphen effect

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haanappel, E.G.; Kycia, S.W.; Harmon, B.N.

1995-07-01

We have measured the de Haas-van Alphen effect in the icosahedral quasicrystal Al{sub 70}Pd{sub 21.5}Mn{sub 8.5}. We have found two well-defined frequencies with the magnetic field parallel to a five-fold axis, and two different ones with the field parallel to a two-fold axis. On increasing the temperature, the amplitude of the oscillations substantially decreased, suggesting that the carriers have large masses.

47 CFR 1.10014 - What happens after officially filing my application?

Code of Federal Regulations, 2010 CFR

2010-10-01

... ARC-xxxxx Foreign Carrier Affiliation Notification FCN-xxxxx International High Frequency IHF-xxxxx... PN released International High Frequency IHF-xxxxx International Public Fixed IPF-xxxxx Recognized... Foreign Carrier Affiliation Notification. International High Frequency: Construction Permits,Licenses...

47 CFR 1.10014 - What happens after officially filing my application?

Code of Federal Regulations, 2011 CFR

2011-10-01

... ARC-xxxxx Foreign Carrier Affiliation Notification FCN-xxxxx International High Frequency IHF-xxxxx... PN released International High Frequency IHF-xxxxx International Public Fixed IPF-xxxxx Recognized... Foreign Carrier Affiliation Notification. International High Frequency: Construction Permits,Licenses...

JAK2 (V617F) mutation is not associated with thrombosis in Behcet syndrome.

PubMed

Ar, M Cem; Hatemi, Gülen; Ekizoğlu, Seda; Bilgen, Hülya; Saçli, Sevgi; Buyru, A Nur; Soysal, Teoman; Ülkü, Birsen; Yazici, Hasan

2012-07-01

The Janus kinase 2(V617F) (JAK2 (V617F)) mutation is an acquired genetic defect that is considered to enhance thrombosis in Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs). Thrombosis is also a well-defined component of Behcet syndrome (BS). The aim of this study was to determine the frequency of JAK2 ( V617F ) mutation in BS-associated thrombosis. A total of 152 patients with BS (62 with thrombosis and 90 without thrombosis) were enrolled. An additional 186 patients with MPNs and 107 healthy blood donors were included to serve as diseased and healthy controls, respectively. None of the patients with BS and healthy controls carried the JAK2 (V617F) mutation, whereas 67% of patients with MPNs were positive for JAK2 ( V617F ). The frequency of thrombosis in patients with MPNs was not statistically different between carriers and non-carriers of JAK2 ( V617F ) mutation. Our data suggest that JAK2 (V617F) is not directly related to thrombosis in MPNs and in other thrombotic entities, such as BS.

Carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool

NASA Astrophysics Data System (ADS)

Cai, Yu; Sha, Shuang

2016-09-01

This paper proposes a new carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool used in a cylindrical borehole environment during oil-based mud drilling processes. The new tool is an orthogonal frequency division multiplexing access-based contactless multi-measurand detection tool. The tool can measure formation resistivity in different azimuthal angles and elevational depths. It can measure many more measurands simultaneously in a specified bandwidth than the legacy frequency division multiplexing multi-measurand tool without a channel-select filter while avoiding inter-carrier interference. The paper also shows that formation resistivity is not sensitive to frequency in certain frequency bands. The average resistivity collected from N subcarriers can increase the measurement of the signal-to-noise ratio (SNR) by N times given no amplitude clipping in the current-injection electrode. If the clipping limit is taken into account, with the phase rotation of each single carrier, the amplitude peak-to-average ratio can be reduced by 3 times, and the SNR can achieve a 9/N times gain over the single-carrier system. The carrier-interleaving technique is also introduced to counter the carrier frequency offset (CFO) effect, where the CFO will cause inter-pad interference. A qualitative analysis and simulations demonstrate that block-interleaving performs better than tone-interleaving when coping with a large CFO. The theoretical analysis also suggests that increasing the subcarrier number can increase the measurement speed or enhance elevational resolution without sacrificing receiver performance. The complex orthogonal multi-pad multi-carrier resistivity logging tool, in which all subcarriers are complex signals, can provide a larger available subcarrier pool than other types of transceivers.

Precise frequency calibration using television video carriers

NASA Technical Reports Server (NTRS)

Burkhardt, Edward E.

1990-01-01

The availability of inexpensive and quick precise frequency calibration methods is limited. VLF and GPS do offer precise calibration. However, antenna placement, cost of equipment, and calibration time place many restrictions on the user. The USNO maintained line-10 television Time of Coincidence (TOC) of station WTTG, channel 5, Washington, DC requires a frequency stable video carrier. This video carrier, 77.24 MHz is controlled by the same cesium beam standard controlling the TOC of line-10. Excellent frequency comparisons against this video carrier have been accomplished at 95 miles (153 km). With stable propagation and a three foot wire antenna, a part in 10(exp 9) can be determined in a few minutes. Inexpensive field equipment with a synthesized 1 kHz offset from the video carrier offers parts in 10(exp 11) calibrations in a few minutes using an oscilloscope as a phase comparator.

Precise frequency calibration using television video carriers

NASA Astrophysics Data System (ADS)

Burkhardt, Edward E.

1990-05-01

The availability of inexpensive and quick precise frequency calibration methods is limited. VLF and GPS do offer precise calibration. However, antenna placement, cost of equipment, and calibration time place many restrictions on the user. The USNO maintained line-10 television Time of Coincidence (TOC) of station WTTG, channel 5, Washington, DC requires a frequency stable video carrier. This video carrier, 77.24 MHz is controlled by the same cesium beam standard controlling the TOC of line-10. Excellent frequency comparisons against this video carrier have been accomplished at 95 miles (153 km). With stable propagation and a three foot wire antenna, a part in 10(exp 9) can be determined in a few minutes. Inexpensive field equipment with a synthesized 1 kHz offset from the video carrier offers parts in 10(exp 11) calibrations in a few minutes using an oscilloscope as a phase comparator.

OFDM Coupled Compressive Sensing Algorithm for Stepped-Frequency Ground Penetrating Radar

DTIC Science & Technology

2014-10-01

These frequencies are combined in such a way to achieve orthogonality between the carrier frequencies, while mitigating any interference between...in such a way to achieve orthogonality between the carrier frequencies, while mitigating any interference between said frequencies. In CS, a signal...frequency tones is mitigated . Orthogonality requires that the sub-bands are spaced at = is the OFDM symbol period, and k is any

Sensitive frequency dependence of the carrier-envelope phase effect on bound-bound transitions: An interference perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng Dian; Fu Panming; Wang Bingbing

2010-11-15

We investigate numerically with Hylleraas coordinates the frequency dependence of the carrier-envelope phase (CEP) effect on bound-bound transitions of helium induced by an ultrashort laser pulse of a few cycles. We find that the CEP effect is very sensitive to the carrier frequency of the laser pulse, occurring regularly even at far-off-resonance frequencies. By analyzing a two-level model, we find that the CEP effect can be attributed to the quantum interference between neighboring multiphoton transition pathways, which is made possible by the broadened spectrum of the ultrashort laser pulse. A general picture is developed along this line to understand themore » sensitivity of the CEP effect to the laser's carrier frequency. Multilevel influence on the CEP effect is also discussed.« less

47 CFR 15.107 - Conducted limits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... not apply to carrier current systems operating as unintentional radiators on frequencies below 30 MHz... carrier current systems containing their fundamental emission within the frequency band 535-1705 kHz and... 50 μH/50 ohms LISN. (3) Carrier current systems operating below 30 MHz are also subject to the...

A model of anuran auditory periphery reveals frequency-dependent adaptation to be a contributing mechanism for two-tone suppression and amplitude modulation coding.

PubMed

Wotton, J M; Ferragamo, M J

2011-10-01

Anuran auditory nerve fibers (ANF) tuned to low frequencies display unusual frequency-dependent adaptation which results in a more phasic response to signals above best frequency (BF) and a more tonic response to signals below. A network model of the first two layers of the anuran auditory system was used to test the contribution of this dynamic peripheral adaptation on two-tone suppression and amplitude modulation (AM) tuning. The model included a peripheral sandwich component, leaky-integrate-and-fire cells and adaptation was implemented by means of a non-linear increase in threshold weighted by the signal frequency. The results of simulations showed that frequency-dependent adaptation was both necessary and sufficient to produce high-frequency-side two-tone suppression for the ANF and cells of the dorsal medullary nucleus (DMN). It seems likely that both suppression and this dynamic adaptation share a common mechanism. The response of ANFs to AM signals was influenced by adaptation and carrier frequency. Vector strength synchronization to an AM signal improved with increased adaptation. The spike rate response to a carrier at BF was the expected flat function with AM rate. However, for non-BF carrier frequencies the response showed a weak band-pass pattern due to the influence of signal sidebands and adaptation. The DMN received inputs from three ANFs and when the frequency tuning of inputs was near the carrier, then the rate response was a low-pass or all-pass shape. When most of the inputs were biased above or below the carrier, then band-pass responses were observed. Frequency-dependent adaptation enhanced the band-pass tuning for AM rate, particularly when the response of the inputs was predominantly phasic for a given carrier. Different combinations of inputs can therefore bias a DMN cell to be especially well suited to detect specific ranges of AM rates for a particular carrier frequency. Such selection of inputs would clearly be advantageous to the frog in recognizing distinct spectral and temporal parameters in communication calls. Copyright © 2011 Elsevier B.V. All rights reserved.

Wide-band analog frequency modulation of optic signals using indirect techniques

NASA Technical Reports Server (NTRS)

Fitzmartin, D. J.; Balboni, E. J.; Gels, R. G.

1991-01-01

The wideband frequency modulation (FM) of an optical carrier by a radio frequency (RF) or microwave signal can be accomplished independent of laser type when indirect modulation is employed. Indirect modulators exploit the integral relation of phase to frequency so that phase modulators can be used to impress frequency modulation on an optical carrier. The use of integrated optics phase modulators, which are highly linear, enables the generation of optical wideband FM signals with very low intermodulation distortion. This modulator can be used as part of an optical wideband FM link for RF and microwave signals. Experimental results from the test of an indirect frequency modulator for an optical carrier are discussed.

Frequency-Diversity Reception for Phase Modulation

NASA Technical Reports Server (NTRS)

Brockman, M. H.

1984-01-01

Signal-to-noise ratio improved. System receives phase modulation transmitted simultaneously on different carrier frequencies. Used for carriers received through different antennas or through same antenna.

Comparing Optical Oscillators across the Air to Milliradians in Phase and 10^{-17} in Frequency.

PubMed

Sinclair, Laura C; Bergeron, Hugo; Swann, William C; Baumann, Esther; Deschênes, Jean-Daniel; Newbury, Nathan R

2018-02-02

We demonstrate carrier-phase optical two-way time-frequency transfer (carrier-phase OTWTFT) through the two-way exchange of frequency comb pulses. Carrier-phase OTWTFT achieves frequency comparisons with a residual instability of 1.2×10^{-17} at 1 s across a turbulent 4-km free space link, surpassing previous OTWTFT by 10-20 times and enabling future high-precision optical clock networks. Furthermore, by exploiting the carrier phase, this approach is able to continuously track changes in the relative optical phase of distant optical oscillators to 9 mrad (7 as) at 1 s averaging, effectively extending optical phase coherence over a broad spatial network for applications such as correlated spectroscopy between distant atomic clocks.

Cystic fibrosis carrier screening in a North American population.

PubMed

Zvereff, Val V; Faruki, Hawazin; Edwards, Marcia; Friedman, Kenneth J

2014-07-01

The aim of this study was to compare the mutation frequency distribution for a 32-mutation panel and a 69-mutation panel used for cystic fibrosis carrier screening. Further aims of the study were to examine the race-specific detection rates provided by both panels and to assess the performance of extended panels in large-scale, population-based cystic fibrosis carrier screening. Although genetic screening for the most common CFTR mutations allows detection of nearly 90% of cystic fibrosis carriers, the large number of other mutations, and their distribution within different ethnic groups, limits the utility of general population screening. Patients referred for cystic fibrosis screening from January 2005 through December 2010 were tested using either a 32-mutation panel (n = 1,601,308 individuals) or a 69-mutation panel (n = 109,830). The carrier frequencies observed for the 69-mutation panel study population (1/36) and Caucasian (1/27) and African-American individuals (1/79) agree well with published cystic fibrosis carrier frequencies; however, a higher carrier frequency was observed for Hispanic-American individuals (1/48) using the 69-mutation panel as compared with the 32-mutation panel (1/69). The 69-mutation panel detected ~20% more mutations than the 32-mutation panel for both African-American and Hispanic-American individuals. Expanded panels using race-specific variants can improve cystic fibrosis carrier detection rates within specific populations. However, it is important that the pathogenicity and the relative frequency of these variants are confirmed.

Carrier-envelope phase dynamics and noise analysis in octave-spanning Ti:sapphire lasers.

PubMed

Matos, Lia; Mücke, Oliver D; Chen, Jian; Kärtner, Franz X

2006-03-20

We investigate the carrier-envelope phase dynamics of octave-spanning Ti:sapphire lasers and perform a complete noise analysis of the carrier-envelope phase stabilization. We model the effect of the laser dynamics on the residual carrier-envelope phase noise by deriving a transfer function representation of the octave-spanning frequency comb. The modelled phase noise and the experimental results show excellent agreement. This greatly enhances our capability of predicting the dependence of the residual carrier-envelope phase noise on the feedback loop filter, the carrier-envelope frequency control mechanism and the pump laser used.

Blind identification of the number of sub-carriers for orthogonal frequency division multiplexing-based elastic optical networking

NASA Astrophysics Data System (ADS)

Zhao, Lei; Xu, Hengying; Bai, Chenglin

2018-03-01

In orthogonal frequency division multiplexing (OFDM)-based elastic optical networking (EON), it is imperative to identify unknown parameters of OFDM-based EON signals quickly, intelligently and robustly. Because the number of sub-carriers determines the size of the sub-carriers spacing and then affects the symbol period of the OFDM and the anti-dispersion capability of the system, the identification of the number of sub-carriers has a profound effect on the identification of other key parameters of the system. In this paper, we proposed a method of number identification for sub-carriers of OFDM-based EON signals with help of high-order cyclic cumulant. The specific fourth-order cyclic cumulant exists only at the location of its sub-carriers frequencies. So the identification of the number of sub-carriers can be implemented by detecting the cyclic-frequencies. The proposed scheme in our study can be divided into three sub-stages, i.e. estimating the spectral range, calculating the high-order cyclic cumulant and identifying the number of sub-carriers. When the optical signal-to-noise ratios (OSNR) varied from 16dB to 22dB, the number of sub-carriers (64-512) was successfully identified in the experiment, and from the statistical point of view, the average identification absolute accuracy (IAAs) exceeded 94%.

Discriminator aided phase lock acquisition for suppressed carrier signals

NASA Technical Reports Server (NTRS)

Carson, L. M.; Krasin, F. E. (Inventor)

1982-01-01

A discriminator aided technique for acquisition of phase lock to a suppressed carrier signal utilizes a Costas loop which is initially operated open loop and control voltage for its VCXO is derived from a phase detector that compares the VCXO to a reference frequency thus establishing coarse frequency resolution with the received signal. Then the Costas loop is closed with the low-pass filter of the channel having a bandwidth much greater (by a factor of about 10) than in the I channel so that a frequency discriminator effect results to aid carrier resolution. Finally, after carrier acquisition, the Q-channel filter of the Costas loop is switched to a bandwidth substantially equal to that of the I-channel for carrier tracking.

Dual frequency optical carrier technique for transmission of reference frequencies in dispersive media

NASA Technical Reports Server (NTRS)

Maleki, Lutfollah (Inventor)

1993-01-01

Two different carrier frequencies modulated by a reference frequency are transmitted to each receiver to be synchronized therewith. Each receiver responds to local phase differences between the two received signals to correct the phase of one of them so as to maintain the corrected signal as a reliable synchronization reference.

System and method for simultaneously collecting serial number information from numerous identity tags

DOEpatents

Doty, Michael A.

1997-01-01

A system and method for simultaneously collecting serial number information reports from numerous colliding coded-radio-frequency identity tags. Each tag has a unique multi-digit serial number that is stored in non-volatile RAM. A reader transmits an ASCII coded "D" character on a carrier of about 900 MHz and a power illumination field having a frequency of about 1.6 Ghz. A one MHz tone is modulated on the 1.6 Ghz carrier as a timing clock for a microprocessor in each of the identity tags. Over a thousand such tags may be in the vicinity and each is powered-up and clocked by the 1.6 Ghz power illumination field. Each identity tag looks for the "D" interrogator modulated on the 900 MHz carrier, and each uses a digit of its serial number to time a response. Clear responses received by the reader are repeated for verification. If no verification or a wrong number is received by any identity tag, it uses a second digital together with the first to time out a more extended period for response. Ultimately, the entire serial number will be used in the worst case collision environments; and since the serial numbers are defined as being unique, the final possibility will be successful because a clear time-slot channel will be available.

System and method for simultaneously collecting serial number information from numerous identity tags

DOEpatents

Doty, M.A.

1997-01-07

A system and method are disclosed for simultaneously collecting serial number information reports from numerous colliding coded-radio-frequency identity tags. Each tag has a unique multi-digit serial number that is stored in non-volatile RAM. A reader transmits an ASCII coded ``D`` character on a carrier of about 900 MHz and a power illumination field having a frequency of about 1.6 Ghz. A one MHz tone is modulated on the 1.6 Ghz carrier as a timing clock for a microprocessor in each of the identity tags. Over a thousand such tags may be in the vicinity and each is powered-up and clocked by the 1.6 Ghz power illumination field. Each identity tag looks for the ``D`` interrogator modulated on the 900 MHz carrier, and each uses a digit of its serial number to time a response. Clear responses received by the reader are repeated for verification. If no verification or a wrong number is received by any identity tag, it uses a second digital together with the first to time out a more extended period for response. Ultimately, the entire serial number will be used in the worst case collision environments; and since the serial numbers are defined as being unique, the final possibility will be successful because a clear time-slot channel will be available. 5 figs.

47 CFR 15.303 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unlicensed Personal..., one below the carrier center frequency and one above the carrier center frequency, that are 26 dB down... transmission burst of the device under all conditions of modulation. Usually this parameter is measured as a...

A joint tracking method for NSCC based on WLS algorithm

NASA Astrophysics Data System (ADS)

Luo, Ruidan; Xu, Ying; Yuan, Hong

2017-12-01

Navigation signal based on compound carrier (NSCC), has the flexible multi-carrier scheme and various scheme parameters configuration, which enables it to possess significant efficiency of navigation augmentation in terms of spectral efficiency, tracking accuracy, multipath mitigation capability and anti-jamming reduction compared with legacy navigation signals. Meanwhile, the typical scheme characteristics can provide auxiliary information for signal synchronism algorithm design. This paper, based on the characteristics of NSCC, proposed a kind of joint tracking method utilizing Weighted Least Square (WLS) algorithm. In this method, the LS algorithm is employed to jointly estimate each sub-carrier frequency shift with the frequency-Doppler linear relationship, by utilizing the known sub-carrier frequency. Besides, the weighting matrix is set adaptively according to the sub-carrier power to ensure the estimation accuracy. Both the theory analysis and simulation results illustrate that the tracking accuracy and sensitivity of this method outperforms the single-carrier algorithm with lower SNR.

Sensitivity to Envelope Interaural Time Differences at High Modulation Rates

PubMed Central

Bleeck, Stefan; McAlpine, David

2015-01-01

Sensitivity to interaural time differences (ITDs) conveyed in the temporal fine structure of low-frequency tones and the modulated envelopes of high-frequency sounds are considered comparable, particularly for envelopes shaped to transmit similar fidelity of temporal information normally present for low-frequency sounds. Nevertheless, discrimination performance for envelope modulation rates above a few hundred Hertz is reported to be poor—to the point of discrimination thresholds being unattainable—compared with the much higher (>1,000 Hz) limit for low-frequency ITD sensitivity, suggesting the presence of a low-pass filter in the envelope domain. Further, performance for identical modulation rates appears to decline with increasing carrier frequency, supporting the view that the low-pass characteristics observed for envelope ITD processing is carrier-frequency dependent. Here, we assessed listeners’ sensitivity to ITDs conveyed in pure tones and in the modulated envelopes of high-frequency tones. ITD discrimination for the modulated high-frequency tones was measured as a function of both modulation rate and carrier frequency. Some well-trained listeners appear able to discriminate ITDs extremely well, even at modulation rates well beyond 500 Hz, for 4-kHz carriers. For one listener, thresholds were even obtained for a modulation rate of 800 Hz. The highest modulation rate for which thresholds could be obtained declined with increasing carrier frequency for all listeners. At 10 kHz, the highest modulation rate at which thresholds could be obtained was 600 Hz. The upper limit of sensitivity to ITDs conveyed in the envelope of high-frequency modulated sounds appears to be higher than previously considered. PMID:26721926

Faster processing of multiple spatially-heterodyned direct to digital holograms

DOEpatents

Hanson, Gregory R.; Bingham, Philip R.

2006-10-03

Systems and methods are described for faster processing of multiple spatially-heterodyned direct to digital holograms. A method includes of obtaining multiple spatially-heterodyned holograms, includes: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first, object beam; applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam; and applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result, wherein digitally recording the first spatially-heterodyned hologram is completed before digitally recording the second spatially-heterodyned hologram and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

Faster processing of multiple spatially-heterodyned direct to digital holograms

DOEpatents

Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN

2008-09-09

Systems and methods are described for faster processing of multiple spatially-heterodyned direct to digital holograms. A method includes of obtaining multiple spatially-heterodyned holograms, includes: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam; applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam; and applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result, wherein digitally recording the first spatially-heterodyned hologram is completed before digitally recording the second spatially-heterodyned hologram and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

Open-loop frequency acquisition for suppressed-carrier biphase signals using one-pole arm filters

NASA Technical Reports Server (NTRS)

Shah, B.; Holmes, J. K.

1991-01-01

Open loop frequency acquisition performance is discussed for suppressed carrier binary phase shift keyed signals in terms of the probability of detecting the carrier frequency offset when the arms of the Costas loop detector have one pole filters. The approach, which does not require symbol timing, uses fast Fourier transforms (FFTs) to detect the carrier frequency offset. The detection probability, which depends on both the 3 dB arm filter bandwidth and the received symbol signal to noise ratio, is derived and is shown to be independent of symbol timing. It is shown that the performance of this technique is slightly better that other open loop acquisition techniques which use integrators in the arms and whose detection performance varies with symbol timing.

49 CFR 390.33 - Commercial motor vehicles used for purposes other than defined.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 5 2014-10-01 2014-10-01 false Commercial motor vehicles used for purposes other than defined. 390.33 Section 390.33 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS FEDERAL MOTOR CARRIER...

Two AFC Loops For Low CNR And High Dynamics

NASA Technical Reports Server (NTRS)

Hinedi, Sami M.; Aguirre, Sergio

1992-01-01

Two alternative digital automatic-frequency-control (AFC) loops proposed to acquire (or reacquire) and track frequency of received carrier radio signal. Intended for use where carrier-to-noise ratios (CNR's) low and carrier frequency characterized by high Doppler shift and Doppler rate because of high relative speed and acceleration, respectively, between transmitter and receiver. Either AFC loops used in place of phase-locked loop. New loop concepts integrate ideas from classical spectrum-estimation, digital-phase-locked-loop, and Kalman-Filter theories.

Carrier phase synchronization system for improved amplitude modulation and television broadcast reception

DOEpatents

Smith, Stephen F [Loudon, TN; Moore, James A [Powell, TN

2011-02-01

Systems and methods are described for carrier phase synchronization for improved AM and TV broadcast reception. A method includes synchronizing the phase of a carrier frequency of a broadcast signal with the phase of a remote reference frequency. An apparatus includes a receiver to detect the phase of a reference signal; a phase comparator coupled to the reference signal-phase receiver; a voltage controlled oscillator coupled to the phase comparator; and a phase-controlled radio frequency output coupled to the voltage controlled oscillator.

Multidimensional signal modulation and/or demodulation for data communications

DOEpatents

Smith, Stephen F [London, TN; Dress, William B [Camas, WA

2008-03-04

Systems and methods are described for multidimensional signal modulation and/or demodulation for data communications. A method includes modulating a carrier signal in a first domain selected from the group consisting of phase, frequency, amplitude, polarization and spread; modulating the carrier signal in a second domain selected from the group consisting of phase, frequency, amplitude, polarization and spread; and modulating the carrier signal in a third domain selected from the group consisting of phase, frequency, amplitude, polarization and spread.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Stephen F; Moore, James A

Systems and methods are described for carrier-frequency synchronization for improved AM and TV broadcast reception. A method includes synchronizing a carrier frequency of a broadcast signal with a remote reference frequency. An apparatus includes a reference signal receiver; a phase comparator coupled to the reference signal receiver; a voltage controlled oscillator coupled to the phase comparator; and a radio frequency output coupled to the voltage controlled oscillator.

Orthogonal Multi-Carrier DS-CDMA with Frequency-Domain Equalization

NASA Astrophysics Data System (ADS)

Tanaka, Ken; Tomeba, Hiromichi; Adachi, Fumiyuki

Orthogonal multi-carrier direct sequence code division multiple access (orthogonal MC DS-CDMA) is a combination of orthogonal frequency division multiplexing (OFDM) and time-domain spreading, while multi-carrier code division multiple access (MC-CDMA) is a combination of OFDM and frequency-domain spreading. In MC-CDMA, a good bit error rate (BER) performance can be achieved by using frequency-domain equalization (FDE), since the frequency diversity gain is obtained. On the other hand, the conventional orthogonal MC DS-CDMA fails to achieve any frequency diversity gain. In this paper, we propose a new orthogonal MC DS-CDMA that can obtain the frequency diversity gain by applying FDE. The conditional BER analysis is presented. The theoretical average BER performance in a frequency-selective Rayleigh fading channel is evaluated by the Monte-Carlo numerical computation method using the derived conditional BER and is confirmed by computer simulation of the orthogonal MC DS-CDMA signal transmission.

Demonstration of an optical frequency synthesizer with zero carrier-envelope-offset frequency stabilized by the direct locking method.

PubMed

Kim, Eok Bong; Lee, Jae-hwan; Trung, Luu Tran; Lee, Wong-Kyu; Yu, Dai-Hyuk; Ryu, Han Young; Nam, Chang Hee; Park, Chang Yong

2009-11-09

We developed an optical frequency synthesizer (OFS) with the carrier-envelope-offset frequency locked to 0 Hz achieved using the "direct locking method." This method differs from a conventional phaselock method in that the interference signal from a self-referencing f-2f interferometer is directly fed back to the carrier-envelope-phase control of a femtosecond laser in the time domain. A comparison of the optical frequency of the new OFS to that of a conventional OFS stabilized by a phase-lock method showed that the frequency comb of the new OFS was not different to that of the conventional OFS within an uncertainty of 5.68x10(-16). As a practical application of this OFS, we measured the absolute frequency of an acetylene-stabilized diode laser serving as an optical frequency standard in optical communications.

Flip-Flop Digital Modulator

NASA Technical Reports Server (NTRS)

Eno, R. F.

1984-01-01

Clock switched on and off in response to data signal. Flip-flop modulator generates square-wave carrier frequency that is half clock frequency and turns carrier on and off. Final demodulator output logical inverse of data input.

Carrier-Envelope Phase Effect on Atomic Excitation by Few-Cycle rf Pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Hebin; Welch, George R.; Sautenkov, Vladimir A.

2010-03-12

We present an experimental and theoretical study of the carrier-envelope phase effects on population transfer between two bound atomic states interacting with intense ultrashort pulses. Radio frequency pulses are used to transfer population among the ground state hyperfine levels in rubidium atoms. These pulses are only a few cycles in duration and have Rabi frequencies of the order of the carrier frequency. The phase difference between the carrier and the envelope of the pulses has a significant effect on the excitation of atomic coherence and population transfer. We provide a theoretical description of this phenomenon using density matrix equations. Wemore » discuss the implications and possible applications of our results.« less

A reprogrammable receiver architecture for wireless signal interception

NASA Astrophysics Data System (ADS)

Yao, Timothy S.

2003-09-01

In this paper, a re-programmable receiver architecture, based on software-defined-radio concept, for wireless signal interception is presented. The radio-frequency (RF) signal that the receiver would like to intercept may come from a terrestrial cellular network or communication satellites, which their carrier frequency are in the range from 800 MHz (civilian mobile) to 15 GHz (Ku band). To intercept signals from such a wide range of frequency in these variant communication systems, the traditional way is to deploy multiple receivers to scan and detect the desired signal. This traditional approach is obviously unattractive due to the cost, efficiency, and accuracy. Instead, we propose a universal receiver, which is software-driven and re-configurable, to intercept signals of interest. The software-defined-radio based receiver first intercepts RF energy of wide spectrum (25MHz) through antenna, performs zero-IF down conversion (homodyne architecture) to baseband, and digital channelizes the baseband signal. The channelization module is a bank of high performance digital filters. The bandwidth of the filter bank is programmable according to the wireless communication protocol under watch. In the baseband processing, high-performance digital signal processors carry out the detection process and microprocessors handle the communication protocols. The baseband processing is also re-configurable for different wireless standards and protocol. The advantages of the software-defined-radio architecture over traditional RF receiver make it a favorable technology for the communication signal interception and surveillance.

Features of anti-inflammatory effects of modulated extremely high-frequency electromagnetic radiation.

PubMed

Gapeyev, Andrew B; Mikhailik, Elena N; Chemeris, Nikolay K

2009-09-01

Using a model of acute zymosan-induced paw edema in NMRI mice, we test the hypothesis that anti-inflammatory effects of extremely high-frequency electromagnetic radiation (EHF EMR) can be essentially modified by application of pulse modulation with certain frequencies. It has been revealed that a single exposure of animals to continuous EHF EMR for 20 min reduced the exudative edema of inflamed paw on average by 19% at intensities of 0.1-0.7 mW/cm(2) and frequencies from the range of 42.2-42.6 GHz. At fixed effective carrier frequency of 42.2 GHz, the anti-inflammatory effect of EHF EMR did not depend on modulation frequencies, that is, application of different modulation frequencies from the range of 0.03-100 Hz did not lead to considerable changes in the effect level. On the contrary, at "ineffective" carrier frequencies of 43.0 and 61.22 GHz, the use of modulation frequencies of 0.07-0.1 and 20-30 Hz has allowed us to restore the effect up to a maximal level. The results obtained show the critical dependence of anti-inflammatory action of low-intensity EHF EMR on carrier and modulation frequencies. Within the framework of this study, the possibility of changing the level of expected biological effect of modulated EMR by a special selection of combination of carrier and modulation frequencies is confirmed.

Evaluation of a GPS Receiver for Code and Carrier-Phase Time and Frequency Transfer

DTIC Science & Technology

2010-11-01

2], and carrier-phase [3]. NIST also employs GPS time transfer as the backup link to Two Way Satellite Time and Frequency Transfer ( TWSTFT ) [4...4] D. Kirchner, 1999, “Two-Way Satellite Time and Frequency Transfer ( TWSTFT ): Principle, Implementation, and Current Performance,” Review of

Unpowered wireless ultrasound tomography system

NASA Astrophysics Data System (ADS)

Zahedi, Farshad; Huang, Haiying

2016-04-01

In this paper, an unpowered wireless ultrasound tomography system is presented. The system consists of two subsystems; the wireless interrogation unit (WIU) and three wireless nodes installed on the structure. Each node is designed to work in generation and sensing modes, but operates at a specific microwave frequency. Wireless transmission of the ultrasound signals between the WIU and the wireless nodes is achieved by converting ultrasound signals to microwave signals and vice versa, using a microwave carrier signal. In the generation mode, both a carrier signal and an ultrasound modulated microwave signal are transmitted to the sensor nodes. Only the node whose operating frequency matches the carrier signal will receive these signals and demodulate them to recover the original ultrasound signal. In the sensing mode, a microwave carrier signal with two different frequency components matching the operating frequencies of the sensor nodes is broadcasted by the WIU. The sensor nodes, in turn, receive the corresponding carrier signals, modulate it with the ultrasound sensing signal, and wirelessly transmit the modulated signal back to the WIU. The demodulation of the sensing signals is performed in the WIU using a digital signal processing. Implementing a software receiver significantly reduces the complexity and the cost of the WIU. A wireless ultrasound tomography system is realized by interchanging the carrier frequencies so that the wireless transducers can take turn to serve as the actuator and sensors.

Methods and apparatuses using filter banks for multi-carrier spread-spectrum signals

DOEpatents

Moradi, Hussein; Farhang, Behrouz; Kutsche, Carl A

2014-10-14

A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to the synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.

Methods and apparatuses using filter banks for multi-carrier spread-spectrum signals

DOEpatents

Moradi, Hussein; Farhang, Behrouz; Kutsche, Carl A

2014-05-20

A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to the synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.

Influence of rate of change of frequency on the overall pitch of frequency-modulated tones.

PubMed

Gockel, H; Moore, B C; Carlyon, R P

2001-02-01

The mechanism(s) determining pitch may assign less weight to portions of a sound where the frequency is changing rapidly. The present experiments explored the possible effect of this on the overall pitch of frequency-modulated sounds. Pitch matches were obtained between an adjustable unmodulated sinusoid and a sinusoidal carrier that was frequency modulated using a highly asymmetric function with the form of a repeating U or inverted U shaped function. The amplitude was constant during the 400-ms presentation time of each stimulus, except for 10-ms raised-cosine onset and offset ramps. In experiment 1, the carrier level was 50 dB SPL and the geometric mean of the instantaneous frequency of the modulated carrier, fc, was either 0.5, 1, 2, or 8 kHz. The modulation rate (fm) was 5, 10, or 20 Hz. The overall depth (maximum to minimum) of the FM was 8% of fc. For all carrier frequencies, the matched frequency was shifted away from the mean carrier frequency, downwards for the U shaped function stimuli and upwards for the repeated inverted U shaped function stimuli. The shift was typically slightly greater than 1% of fc, and did not vary markedly with fc. The effect of fm was small, but there was a trend for the shifts to decrease with increasing fm for fc = 0.5 kHz and to increase with increasing fm for fc = 2 kHz. In experiment 2, the carrier level was reduced to 20 dB SL and matches were obtained only for fc = 2 kHz. Shifts in matched frequency of about 1% were still observed, but the trend for the shifts to increase with increasing fm no longer occurred. In experiment 3, matches were obtained for a 4-kHz carrier at 50 dB SPL. Shifts of about 1% again occurred, which did not vary markedly with fm. The shifts in matched frequency observed in all three experiments are not predicted by models based on the amplitude- or intensity-weighted average of instantaneous frequency (EWAIF or IWAIF). The shifts (and the pitch shifts observed earlier for two-tone complexes and for stimuli with simultaneous AM and FM) are consistent with a model based on the assumption that the overall pitch of a frequency-modulated sound is determined from a weighted average of period estimates, with the weight attached to a given estimate being inversely related to the short-term rate of change of period and directly related to a compressive function of the amplitude.

Theoretical study of low-frequency noise and amplitude – frequency characteristics of a semiconductor laser with a fiber Bragg grating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurnosov, V D; Kurnosov, K V

2013-09-30

Using the rate equations for the density of photons and charge carriers, we have studied the amplitude low-frequency noise of a fibre Bragg grating semiconductor laser. The calculations rely on two versions of the rate equation for the carriers, characterised by the presence of the optical confinement coefficient for the term, which takes into account the rate of stimulated recombination. It is shown that the relative noise intensity, which is calculated by using the rate equation for the carriers without optical confinement, agrees better with the experimental results. The calculation of the amplitude – frequency characteristics (AFCs) has shown thatmore » it is impossible to give preference to any one of these systems, since the AFCs for the two versions of the rate equations for the carriers coincide. (lasers)« less

High-Accuracy Quartic Force Field Calculations for the Spectroscopic Constants and Vibrational Frequencies of 1(exp 1)A' l-C3H(-): A Possible Link to Lines Observed in the Horsehead Nebula PDR

NASA Technical Reports Server (NTRS)

Fortenberry, Ryan C.; Huang, Xinchuan; Crawford, T. Daniel; Lee, Timothy J.

2013-01-01

It has been shown that rotational lines observed in the Horsehead nebula photon-dominated-region (PDR) are probably not caused by l-C3H+, as was originally suggested. In the search for viable alternative candidate carriers, quartic force fields are employed here to provide highly accurate rotational constants, as well as fundamental vibrational frequencies, for another candidate carrier: 1 (sup 1)A' C3H(-). The ab initio computed spectroscopic constants provided in this work are, compared to those necessary to define the observed lines, as accurate as the computed spectroscopic constants for many of the known interstellar anions. Additionally, the computed D-eff for C3H(-) is three times closer to the D deduced from the observed Horsehead nebula lines relative to l-C3H(+). As a result, 1 (sup 1)A' C3H(-). is a more viable candidate for these observed rotational transitions and would be the seventh confirmed interstellar anion detected within the past decade and the first C(sub n)H(-) molecular anion with an odd n.

Preconceptional identification of cystic fibrosis carriers in the Sardinian population: A pilot screening program.

PubMed

Coiana, Alessandra; Faa', Valeria; Carta, Daniela; Puddu, Rosalba; Cao, Antonio; Rosatelli, Maria Cristina

2011-05-01

In Sardinia the mutational spectrum of CFTR gene is well defined. A mutation detection rate of 94% can be achieved by screening for 15 CFTR mutations with a frequency higher than 0.5%. The efficiency of this molecular test suggests that Sardinians may represent a suitable population for a preconceptional screening. Five hundred couples of Sardinia descent were screened for 38 mutations using a semi-automated reverse-dot blot and PCR-gel electrophoresis assays. This mutation panel included the 15 most frequent CF alleles in Sardinia. We identified 38 CF carriers, revealing an overall frequency of 1/25 (4%). The most common CF allele was the p.Thr338Ile (T338I) (65%), followed by the p.Phe508del (F508del) (22.5%). We also identified one couple at risk and an asymptomatic female homozygote for the p.Thr338Ile allele. In spite of the low number of the couples tested, the results herein reported demonstrate the efficacy and efficiency of the preconceptional screening program and the high participation rate of the Sardinian population (99%). Copyright © 2010 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Apparatus for direct-to-digital spatially-heterodyned holography

DOEpatents

Thomas, Clarence E.; Hanson, Gregory R.

2006-12-12

An apparatus operable to record a spatially low-frequency heterodyne hologram including spatially heterodyne fringes for Fourier analysis includes: a laser; a beamsplitter optically coupled to the laser; an object optically coupled to the beamsplitter; a focusing lens optically coupled to both the beamsplitter and the object; a digital recorder optically coupled to the focusing lens; and a computer that performs a Fourier transform, applies a digital filter, and performs an inverse Fourier transform. A reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form a spatially low-frequency heterodyne hologram including spatially heterodyne fringes for Fourier analysis which is recorded by the digital recorder, and the computer transforms the recorded spatially low-frequency heterodyne hologram including spatially heterodyne fringes and shifts axes in Fourier space to sit on top of a heterodyne carrier frequency defined by an angle between the reference beam and the object beam and cuts off signals around an original origin before performing the inverse Fourier transform.

Interaural time discrimination of envelopes carried on high-frequency tones as a function of level and interaural carrier mismatch

PubMed Central

Blanks, Deidra A.; Buss, Emily; Grose, John H.; Fitzpatrick, Douglas C.; Hall, Joseph W.

2009-01-01

Objectives The present study investigated interaural time discrimination for binaurally mismatched carrier frequencies in listeners with normal hearing. One goal of the investigation was to gain insights into binaural hearing in patients with bilateral cochlear implants, where the coding of interaural time differences may be limited by mismatches in the neural populations receiving stimulation on each side. Design Temporal envelopes were manipulated to present low frequency timing cues to high frequency auditory channels. Carrier frequencies near 4 kHz were amplitude modulated at 128 Hz via multiplication with a half-wave rectified sinusoid, and that modulation was either in-phase across ears or delayed to one ear. Detection thresholds for non-zero interaural time differences were measured for a range of stimulus levels and a range of carrier frequency mismatches. Data were also collected under conditions designed to limit cues based on stimulus spectral spread, including masking and truncation of sidebands associated with modulation. Results Listeners with normal hearing can detect interaural time differences in the face of substantial mismatches in carrier frequency across ears. Conclusions The processing of interaural time differences in listeners with normal hearing is likely based on spread of excitation into binaurally matched auditory channels. Sensitivity to interaural time differences in listeners with cochlear implants may depend upon spread of current that results in the stimulation of neural populations that share common tonotopic space bilaterally. PMID:18596646

Methods and devices based on brillouin selective sideband amplification

NASA Technical Reports Server (NTRS)

Yao, X. Steve (Inventor)

2003-01-01

Opto-electronic devices and techniques using Brillouin scattering to select a sideband in a modulated optical carrier signal for amplification. Two lasers respectively provide a carrier signal beam and a Brillouin pump beam which are fed into an Brillouin optical medium in opposite directions. The relative frequency separation between the lasers is adjusted to align the frequency of the backscattered Brillouin signal with a desired sideband in the carrier signal to effect a Brillouin gain on the sideband. This effect can be used to implement photonic RF signal mixing and conversion with gain, conversion from phase modulation to amplitude modulation, photonic RF frequency multiplication, optical and RF pulse generation and manipulation, and frequency-locking of lasers.

Radio-Frequency and Wideband Modulation Arraying

NASA Technical Reports Server (NTRS)

Brockman, M. H.

1984-01-01

Summing network receives coherent signals from all receivers in array. Method sums narrow-band radio-frequency (RF) carrier powers and wide-band spectrum powers of array of separate antenna/receiver systems designed for phase-locked-loop or suppressed-carrier operation.

An assessment of envelope-based demodulation in case of proximity of carrier and modulation frequencies

NASA Astrophysics Data System (ADS)

Shahriar, Md Rifat; Borghesani, Pietro; Randall, R. B.; Tan, Andy C. C.

2017-11-01

Demodulation is a necessary step in the field of diagnostics to reveal faults whose signatures appear as an amplitude and/or frequency modulation. The Hilbert transform has conventionally been used for the calculation of the analytic signal required in the demodulation process. However, the carrier and modulation frequencies must meet the conditions set by the Bedrosian identity for the Hilbert transform to be applicable for demodulation. This condition, basically requiring the carrier frequency to be sufficiently higher than the frequency of the modulation harmonics, is usually satisfied in many traditional diagnostic applications (e.g. vibration analysis of gear and bearing faults) due to the order-of-magnitude ratio between the carrier and modulation frequency. However, the diversification of the diagnostic approaches and applications shows cases (e.g. electrical signature analysis-based diagnostics) where the carrier frequency is in close proximity to the modulation frequency, thus challenging the applicability of the Bedrosian theorem. This work presents an analytic study to quantify the error introduced by the Hilbert transform-based demodulation when the Bedrosian identity is not satisfied and proposes a mitigation strategy to combat the error. An experimental study is also carried out to verify the analytical results. The outcome of the error analysis sets a confidence limit on the estimated modulation (both shape and magnitude) achieved through the Hilbert transform-based demodulation in case of violated Bedrosian theorem. However, the proposed mitigation strategy is found effective in combating the demodulation error aroused in this scenario, thus extending applicability of the Hilbert transform-based demodulation.

ADH1B polymorphism, alcohol consumption, and binge drinking in Slavic Caucasians: results from the Czech HAPIEE study.

PubMed

Hubacek, Jaroslav A; Pikhart, Hynek; Peasey, Anne; Kubinova, Ruzena; Bobak, Martin

2012-05-01

Several genetic polymorphisms influence the risk of heavy alcohol consumption but it is not well understood whether the genetic effects are similar in different populations and drinking cultures, nor whether the genetic influences on binge drinking are similar to those seen for alcoholism. We have analyzed the effect of the Arg47His (rs1229984) variant within the alcohol dehydrogenase (ADH1B) gene on a range of drinking related variables in a large Eastern European Slavic population (Czech HAPIEE study), which recruited random samples of men and women aged 45-69 years in 7 Czech towns (3,016 males and 3,481 females with complete data). Drinking frequency, annual alcohol intake, prevalence of binge drinking (≥100 g in men and ≥60 g in women at least once a month) and the mean dose of alcohol per occasion were measured by the graduated frequency questionnaire. Alcohol intake in a typical week was used to define heavy drinking (≥350 g/wk in men and ≥210 g in women). Problem drinking (≥2 positive answers on CAGE) and negative consequences of drinking on different aspects of life were also measured. The frequency of the His47 allele carriers was 11%. Homozygotes in the common allele (Arg47Arg), among both males and females, had significantly higher drinking frequency, and annual and weekly intake of alcohol than His47 carriers. The odds ratio of heavy drinking in Arg47Arg homozygotes versus His47 carriers was 2.1 (95% confidence intervals 1.1-3.2) in men and 2.2 (1.0-4.7) in women. In females, but not in males, Arg47Arg homozygotes had marginally significantly higher prevalence of binge drinking and mean alcohol dose per drinking session. There was no consistent association with problem drinking and negative consequences of drinking. The ADH1B genotype was associated with the frequency and volume of drinking but its associations with binge drinking and problem drinking were less consistent. Copyright © 2011 by the Research Society on Alcoholism.

Self-similar gravity wave spectra resulting from the modulation of bound waves

NASA Astrophysics Data System (ADS)

Michel, Guillaume; Semin, Benoît; Cazaubiel, Annette; Haudin, Florence; Humbert, Thomas; Lepot, Simon; Bonnefoy, Félicien; Berhanu, Michaël; Falcon, Éric

2018-05-01

We experimentally study the properties of nonlinear surface gravity waves in a large-scale basin. We consider two different configurations: a one-dimensional (1D) monochromatic wave forcing, and a two-dimensional (2D) forcing with bichromatic waves satisfying resonant-wave interaction conditions. For the 1D forcing, we find a discrete wave-energy spectrum dominated at high frequencies by bound waves whose amplitudes decrease as a power law of the frequency. Bound waves (e.g., to the carrier) are harmonics superimposed on the carrier wave propagating with the same phase velocity as the one of the carrier. When a narrow frequency random modulation is applied to this carrier, the high-frequency part of the wave-energy spectrum becomes continuous with the same frequency-power law. Similar results are found for the 2D forcing when a random modulation is also applied to both carrier waves. Our results thus show that all these nonlinear gravity wave spectra are dominated at high frequencies by the presence of bound waves, even in the configuration where resonant interactions occur. Moreover, in all these configurations, the power-law exponent of the spectrum is found to depend on the forcing amplitude with the same trend as the one found in previous gravity wave turbulence experiments. Such a set of bound waves may thus explain this dependence that was previously poorly understood.

Frequency Dependent Harmonic Powers in a Modified Uni-Traveling Carrier (MUTC) Photodetector

DTIC Science & Technology

2017-01-27

Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/5651--17-9712 Frequency Dependent Harmonic Powers in a Modified Uni- Traveling Carrier...burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing...Modified Uni- Traveling Carrier (MUTC) Photodetector Yue Hu,* Meredith N. Hutchinson, and Curtis R. Menyuk* Naval Research Laboratory 4555 Overlook

A new approach to harmonic elimination based on a real-time comparison method

NASA Astrophysics Data System (ADS)

Gourisetti, Sri Nikhil Gupta

Undesired harmonics are responsible for noise in a transmission channel, power loss in power electronics and in motor control. Selective Harmonic Elimination (SHE) is a well-known method used to eliminate or suppress the unwanted harmonics between the fundamental and the carrier frequency harmonic/component. But SHE bears the disadvantage of its incapability to use in real-time applications. A novel reference-carrier comparative method has been developed which can be used to generate an SPWM signal to apply in real-time systems. A modified carrier signal is designed and tested for different carrier frequencies based on the generated SPWM FFT. The carrier signal may change for different fundamental to carrier ratio that leads to solving the equations each time. An analysis to find all possible solutions for a particular carrier frequency and fundamental amplitude is performed and found. This proves that there is no one global maxima instead several local maximas exists for a particular condition set that makes this method less sensitive. Additionally, an attempt to find a universal solution that is valid for any carrier signal with predefined fundamental amplitude is performed. A uniform distribution Monte-Carlo sensitivity analysis is performed to measure the window i.e., best and worst possible solutions. The simulations are performed using MATLAB and are justified with experimental results.

Optical frequency upconversion technique for transmission of wireless MIMO-type signals over optical fiber.

PubMed

Shaddad, R Q; Mohammad, A B; Al-Gailani, S A; Al-Hetar, A M

2014-01-01

The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF). The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C) modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM). The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength.

Spectrotemporal modulation sensitivity for hearing-impaired listeners: dependence on carrier center frequency and the relationship to speech intelligibility.

PubMed

Mehraei, Golbarg; Gallun, Frederick J; Leek, Marjorie R; Bernstein, Joshua G W

2014-07-01

Poor speech understanding in noise by hearing-impaired (HI) listeners is only partly explained by elevated audiometric thresholds. Suprathreshold-processing impairments such as reduced temporal or spectral resolution or temporal fine-structure (TFS) processing ability might also contribute. Although speech contains dynamic combinations of temporal and spectral modulation and TFS content, these capabilities are often treated separately. Modulation-depth detection thresholds for spectrotemporal modulation (STM) applied to octave-band noise were measured for normal-hearing and HI listeners as a function of temporal modulation rate (4-32 Hz), spectral ripple density [0.5-4 cycles/octave (c/o)] and carrier center frequency (500-4000 Hz). STM sensitivity was worse than normal for HI listeners only for a low-frequency carrier (1000 Hz) at low temporal modulation rates (4-12 Hz) and a spectral ripple density of 2 c/o, and for a high-frequency carrier (4000 Hz) at a high spectral ripple density (4 c/o). STM sensitivity for the 4-Hz, 4-c/o condition for a 4000-Hz carrier and for the 4-Hz, 2-c/o condition for a 1000-Hz carrier were correlated with speech-recognition performance in noise after partialling out the audiogram-based speech-intelligibility index. Poor speech-reception and STM-detection performance for HI listeners may be related to a combination of reduced frequency selectivity and a TFS-processing deficit limiting the ability to track spectral-peak movements.

Usage Autocorrelation Function in the Capacity of Indicator Shape of the Signal in Acoustic Emission Testing of Intricate Castings

NASA Astrophysics Data System (ADS)

Popkov, Artem

2016-01-01

The article contains information about acoustic emission signals analysing using autocorrelation function. Operation factors were analysed, such as shape of signal, the origins time and carrier frequency. The purpose of work is estimating the validity of correlations methods analysing signals. Acoustic emission signal consist of different types of waves, which propagate on different trajectories in object of control. Acoustic emission signal is amplitude-, phase- and frequency-modeling signal. It was described by carrier frequency at a given point of time. Period of signal make up 12.5 microseconds and carrier frequency make up 80 kHz for analysing signal. Usage autocorrelation function like indicator the origin time of acoustic emission signal raises validity localization of emitters.

Carrier-phase-based two-way satellite time and frequency transfer.

PubMed

Fujieda, Miho; Gotoh, Tadahiro; Nakagawa, Fumimaru; Tabuchi, Ryo; Aida, Masanori; Amagai, Jun

2012-12-01

We performed measurements of carrier-phase-based two-way satellite time and frequency transfer (TWST-FT) with an A/D sampler and conventional TWSTFT system. We found that an instability resulting from a local signal at the satellite transponder was negligible. The short-term stability of 4 × 10(-13) at 1 s was achieved in a short-baseline measurement. The results showed good agreement with the GPS carrier phase.

Photonics-based microwave frequency measurement using a double-sideband suppressed-carrier modulation and an InP integrated ring-assisted Mach-Zehnder interferometer filter.

PubMed

Fandiño, Javier S; Muñoz, Pascual

2013-11-01

A photonic system capable of estimating the unknown frequency of a CW microwave tone is presented. The core of the system is a complementary optical filter monolithically integrated in InP, consisting of a ring-assisted Mach-Zehnder interferometer with a second-order elliptic response. By simultaneously measuring the different optical powers produced by a double-sideband suppressed-carrier modulation at the outputs of the photonic integrated circuit, an amplitude comparison function that depends on the input tone frequency is obtained. Using this technique, a frequency measurement range of 10 GHz (5-15 GHz) with a root mean square value of frequency error lower than 200 MHz is experimentally demonstrated. Moreover, simulations showing the impact of a residual optical carrier on system performance are also provided.

ACSS2 gene variant associated with cleft lip and palate in two independent Hispanic populations.

PubMed

Dodhia, Sonam; Celis, Katrina; Aylward, Alana; Cai, Yi; Fontana, Maria E; Trespalacios, Alberto; Hoffman, David C; Alfonso, Henry Ostos; Eisig, Sidney B; Su, Gloria H; Chung, Wendy K; Haddad, Joseph

2017-10-01

A candidate variant (p.Val496Ala) of the ACSS2 gene (T > C missense, rs59088485 variant at chr20: bp37 33509608) was previously found to consistently segregate with nonsyndromic cleft lip and/or palate (NSCLP) in three Honduran families. Objectives of this study were 1) to investigate the frequency of this ACSS2 variant in Honduran unrelated NSCLP patients and unrelated unaffected controls and 2) to investigate the frequency of this variant in Colombian unrelated affected NSCLP patients and unrelated unaffected controls. Case-control studies. Sanger sequencing of 99 unrelated Honduran NSCLP patients and 215 unrelated unaffected controls for the p.Val496Ala ACSS2 variant was used to determine the carrier frequency in NSCLP patients and controls. Sanger sequencing of 230 unrelated Colombian NSCLP patients and 146 unrelated unaffected controls for the p.Val496Ala ACSS2 variant was used to determine the carrier frequency in NSCLP patients and controls. In the Honduran population, the odds ratio of having NSCLP among carriers of the p.Val496Ala ACSS2 variant was 4.0 (P = .03), with a carrier frequency of seven of 99 (7.1%) in unrelated affected and four of 215 (1.9%) in unrelated unaffected individuals. In the Colombian population, the odds ratio of having NSCLP among carriers of the p.Val496Ala ACSS2 variant was 2.6 (P = .04), with a carrier frequency of 23 of 230 (10.0%) in unrelated affected and six of 146 (4.1%) in unrelated unaffected individuals. These findings support the role of ACSS2 in NSCLP in two independent Hispanic populations from Honduras and Colombia. NA Laryngoscope, 127:E336-E339, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Modulator for tone and binary signals. [phase of modulation of tone and binary signals on carrier waves in communication systems

NASA Technical Reports Server (NTRS)

Mcchesney, J. R.; Lerner, T.; Fitch, E. J. (Inventor)

1975-01-01

Tones and binary information are transmitted as phase variations on a carrier wave of constant amplitude and frequency. The carrier and tones are applied to a balanced modulator for deriving an output signal including a pair of sidebands relative to the carrier. The carrier is phase modulated by a digital signal so that it is + or - 90 deg out of phase with the predetermined phase of the carrier. The carrier is combined in an algebraic summing device with the phase modulated signal and the balanced modulator output signal. The output of the algebraic summing device is hard limited to derive a constant amplitude and frequency signal having very narrow bandwidth requirements. At a receiver, the tones and binary data are detected with a phase locked loop having a voltage controlled oscillator driving a pair of orthogonal detection channels.

Methods and apparatuses using filter banks for multi-carrier spread spectrum signals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moradi, Hussein; Farhang, Behrouz; Kutsche, Carl A

2017-01-31

A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to themore » synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.« less

Methods and apparatuses using filter banks for multi-carrier spread spectrum signals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moradi, Hussein; Farhang, Behrouz; Kutsche, Carl A.

2016-06-14

A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to themore » synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.« less

Code-Phase Clock Bias and Frequency Offset in PPP Clock Solutions.

PubMed

Defraigne, Pascale; Sleewaegen, Jean-Marie

2016-07-01

Precise point positioning (PPP) is a zero-difference single-station technique that has proved to be very effective for time and frequency transfer, enabling the comparison of atomic clocks with a precision of a hundred picoseconds and a one-day stability below the 1e-15 level. It was, however, noted that for some receivers, a frequency difference is observed between the clock solution based on the code measurements and the clock solution based on the carrier-phase measurements. These observations reveal some inconsistency either between the code and carrier phases measured by the receiver or between the data analysis strategy of codes and carrier phases. One explanation for this discrepancy is the time offset that can exist for some receivers between the code and the carrier-phase latching. This paper explains how a code-phase bias in the receiver hardware can induce a frequency difference between the code and the carrier-phase clock solutions. The impact on PPP is then quantified. Finally, the possibility to determine this code-phase bias in the PPP modeling is investigated, and the first results are shown to be inappropriate due to the high level of code noise.

49 CFR 325.5 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS General Provisions § 325.5 Definitions. (a) Statutory definitions. All terms defined in the Noise...) Definitions in standards. All terms defined in § 202.10 of the Interstate Motor Carrier Noise Emission...

49 CFR 325.5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS General Provisions § 325.5 Definitions. (a) Statutory definitions. All terms defined in the Noise...) Definitions in standards. All terms defined in § 202.10 of the Interstate Motor Carrier Noise Emission...

47 CFR 54.411 - Link Up program defined.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 3 2011-10-01 2011-10-01 false Link Up program defined. 54.411 Section 54.411 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL... low-income consumers, which an eligible telecommunications carrier shall offer as part of its...

Multicarrier orthogonal spread-spectrum (MOSS) data communications

DOEpatents

Smith, Stephen F [London, TN; Dress, William B [Camas, WA

2008-01-01

Systems and methods are described for multicarrier orthogonal spread-spectrum (MOSS) data communication. A method includes individually spread-spectrum modulating at least two of a set of orthogonal frequency division multiplexed carriers, wherein the resulting individually spread-spectrum modulated at least two of a set of orthogonal frequency division multiplexed carriers are substantially mutually orthogonal with respect to both frequency division multiplexing and spread-spectrum modulation.

Parallel PWMs Based Fully Digital Transmitter with Wide Carrier Frequency Range

PubMed Central

Zhou, Bo; Zhang, Kun; Zhou, Wenbiao; Zhang, Yanjun; Liu, Dake

2013-01-01

The carrier-frequency (CF) and intermediate-frequency (IF) pulse-width modulators (PWMs) based on delay lines are proposed, where baseband signals are conveyed by both positions and pulse widths or densities of the carrier clock. By combining IF-PWM and precorrected CF-PWM, a fully digital transmitter with unit-delay autocalibration is implemented in 180 nm CMOS for high reconfiguration. The proposed architecture achieves wide CF range of 2 M–1 GHz, high power efficiency of 70%, and low error vector magnitude (EVM) of 3%, with spectrum purity of 20 dB optimized in comparison to the existing designs. PMID:24223503

Reconfigurable optical-to-optical frequency conversion method and apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zortman, William A.; Lentine, Anthony L.

A photonic device is provided for impressing a modulation pattern on an optical carrier. The device includes a unit in which a photodetector and an optical microresonator are monolithically integrated. The device further includes an optical waveguide evanescently coupled to the optical microresonator and having at least an upstream portion configured to carry at least one optical carrier toward the microresonator. The optical microresonator is tunable so as to resonate with the optical carrier frequency. The optical microresonator and the photodetector are mutually coupled such that in operation, charge carriers photogenerated in the photodetector are injected into the microresonator, wheremore » the photocurrent changes the resonant conditions. In some embodiments the device is operable as an optical-to-optical frequency converter. In other embodiments the device is operable as an oscillator.« less

Apparatus and methods of measuring minority carrier lifetime using a liquid probe

DOEpatents

Li, Jian

2016-04-12

Methods and apparatus for measuring minority carrier lifetimes using liquid probes are provided. In one embodiment, a method of measuring the minority carrier lifetime of a semiconductor material comprises: providing a semiconductor material having a surface; forming a rectifying junction at a first location on the surface by temporarily contacting the surface with a conductive liquid probe; electrically coupling a second junction to the semiconductor material at a second location, wherein the first location and the second location are physically separated; applying a forward bias to the rectifying junction causing minority carrier injection in the semiconductor material; measuring a total capacitance as a function of frequency between the rectifying junction and the second junction; determining an inflection frequency of the total capacitance; and determining a minority lifetime of the semiconductor material from the inflection frequency.

47 CFR 73.322 - FM stereophonic sound transmission standards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... frequency in a transmission system meeting the following parameters: (1) The modulating signal for the main... frequency modulate the main carrier between the limits of 8 and 10 percent. (3) One stereophonic subcarrier... stereophomic subcarriers are not precluded. (4) Double sideband, suppressed-carrier, amplitude modulation of...

47 CFR 15.207 - Conducted limits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... apply to carrier current systems operating as intentional radiators on frequencies below 30 MHz. In lieu... current system containing their fundamental emission within the frequency band 535-1705 kHz and intended.../50 ohms LISN. (3) Carrier current systems operating below 30 MHz are also subject to the radiated...

Spectrotemporal modulation sensitivity for hearing-impaired listeners: Dependence on carrier center frequency and the relationship to speech intelligibility

PubMed Central

Mehraei, Golbarg; Gallun, Frederick J.; Leek, Marjorie R.; Bernstein, Joshua G. W.

2014-01-01

Poor speech understanding in noise by hearing-impaired (HI) listeners is only partly explained by elevated audiometric thresholds. Suprathreshold-processing impairments such as reduced temporal or spectral resolution or temporal fine-structure (TFS) processing ability might also contribute. Although speech contains dynamic combinations of temporal and spectral modulation and TFS content, these capabilities are often treated separately. Modulation-depth detection thresholds for spectrotemporal modulation (STM) applied to octave-band noise were measured for normal-hearing and HI listeners as a function of temporal modulation rate (4–32 Hz), spectral ripple density [0.5–4 cycles/octave (c/o)] and carrier center frequency (500–4000 Hz). STM sensitivity was worse than normal for HI listeners only for a low-frequency carrier (1000 Hz) at low temporal modulation rates (4–12 Hz) and a spectral ripple density of 2 c/o, and for a high-frequency carrier (4000 Hz) at a high spectral ripple density (4 c/o). STM sensitivity for the 4-Hz, 4-c/o condition for a 4000-Hz carrier and for the 4-Hz, 2-c/o condition for a 1000-Hz carrier were correlated with speech-recognition performance in noise after partialling out the audiogram-based speech-intelligibility index. Poor speech-reception and STM-detection performance for HI listeners may be related to a combination of reduced frequency selectivity and a TFS-processing deficit limiting the ability to track spectral-peak movements. PMID:24993215

Both hemophilia health care providers and hemophilia a carriers report that carriers have excessive bleeding.

PubMed

Paroskie, Allison; Oso, Olatunde; Almassi, Benjamin; DeBaun, Michael R; Sidonio, Robert F

2014-05-01

Hemophilia A, the result of reduced factor VIII activity, is an X-linked recessive bleeding disorder. Previous reports of hemophilia A carriers suggest an increased bleeding tendency. Our objective was to determine the attitudes and understanding of the hemophilia A carrier bleeding phenotype, and opinions regarding timing of carrier testing from the perspective of both medical providers and affected patients. Data from this survey were used as preliminary data for an ongoing prospective study. An electronic survey was distributed to physicians and nurses employed at Hemophilia Treatment Centers, and hemophilia A carriers who were members of Hemophilia Federation of America. The questions focused on the clinical understanding of bleeding symptoms and management of hemophilia A carriers, and the timing and intensity of carrier testing. Our survey indicates that 51% (36/51) of providers compared with 78% (36/46) of carriers believe that hemophilia A carriers with normal factor VIII activity have an increased bleeding tendency (P<0.001); 72% (33/36) of hemophilia A carriers report a high frequency of bleeding symptoms. Regarding carrier testing, 72% (50/69) of medical providers recommend testing after 14 years of age, conversely 65% (29/45) of hemophilia A carriers prefer testing to be done before this age (P<0.001). Hemophilia A carriers self-report a higher frequency of bleeding than previously acknowledged, and have a preference for earlier testing to confirm carrier status.

Optical Frequency Upconversion Technique for Transmission of Wireless MIMO-Type Signals over Optical Fiber

PubMed Central

Shaddad, R. Q.; Mohammad, A. B.; Al-Gailani, S. A.; Al-Hetar, A. M.

2014-01-01

The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF). The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C) modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM). The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength. PMID:24772009

Analysis of OFDMA receiver with carrier frequency offset and common carrier frequency offset (CCFO)

NASA Astrophysics Data System (ADS)

Gauni, Sabitha; Kumar, R.

2013-01-01

The technique of Orthogonal frequency multiplexing (OFDM) is used to mitigate the multipath effects and to achieve better data rate. When these systems are extended to enable multiple access wireless multimedia communications they are more beneficial. The performance of the OFDM systems degrades with frequency offset and phase offset. The OFDM multiple access (OFDMA) technology allots groups of the OFDM subcarriers allocated to different users for transmission. In this paper we study the interference effects of the individual subcarriers with the neighbouring subcarriers which also plays a role in the system degradation is termed as Multiuser Interference (MUI). The effect of Carrier frequency offset (CFO) on these systems is also taken in account. There are conventional CFO compensation methods for OFDMA systems the CFOs are usually compensated by directly eliminating the intercarrier interference (ICI) caused by the residual CFOs for individual users.

EQUALIZING THE ELECTRIC FIELD INTENSITY WITHIN CHICK BRAIN IMMERSED IN BUFFER SOLUTION AT DIFFERENT CARRIER FREQUENCIES

EPA Science Inventory

Presented here are the numerical relationships between incident power densities that produce the same average electric field intensity within a chick brain half immersed in buffered saline solution and exposed to a uniform electromagnetic field at carrier frequencies of 50, 147, ...

BIOLOGICAL INFLUENCES OF LOW-FREQUENCY SINUSOIDAL ELECTROMAGNETIC SIGNALS ALONE AND SUPERIMPOSED ON RF CARRIER WAVES

EPA Science Inventory

The report describes in a historical context the experiments that have been performed to examine the biological responses caused by exposure to low frequency electromagnetic radiation directly or as modulation of RF carrier waves. A detailed review is provided of the independentl...

System Design Plan for a DCS (Defense Communications System) Data Transmission Network.

DTIC Science & Technology

1981-07-01

modems , FDO group modems , and Voice Frequency Carrier Telegraph (VFCT) networks. The DTN will be a synchronous network and its implementation must coincide...Frequency (VF) modems and Voice Frequency Carrier Telegraph (VFCT) networks. Further, data circuits can be extended over present analog FDM facilities using...VF or group data modems . In addition to the availability of terrestrial and satellite digital transmission facilities, the implementation of the DTN

Dual-sensitivity profilometry with defocused projection of binary fringes.

PubMed

Garnica, G; Padilla, M; Servin, M

2017-10-01

A dual-sensitivity profilometry technique based on defocused projection of binary fringes is presented. Here, two sets of fringe patterns with a sinusoidal profile are produced by applying the same analog low-pass filter (projector defocusing) to binary fringes with a high- and low-frequency spatial carrier. The high-frequency fringes have a binary square-wave profile, while the low-frequency binary fringes are produced with error-diffusion dithering. The binary nature of the binary fringes removes the need for calibration of the projector's nonlinear gamma. Working with high-frequency carrier fringes, we obtain a high-quality wrapped phase. On the other hand, working with low-frequency carrier fringes we found a lower-quality, nonwrapped phase map. The nonwrapped estimation is used as stepping stone for dual-sensitivity temporal phase unwrapping, extending the applicability of the technique to discontinuous (piecewise continuous) surfaces. We are proposing a single defocusing level for faster high- and low-frequency fringe data acquisition. The proposed technique is validated with experimental results.

A Precision, Low-Cost GPS-Based Transmitter Synchronization Scheme for Improved AM Reception

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Stephen Fulton; Moore, Anthony

2009-01-01

This paper describes a highly accurate carrier-frequency synchronization scheme for actively, automatically locking multiple, remotely located AM broadcast transmitters to a common frequency/timing reference source such as GPS. The extremely tight frequency lock (to {approx}1 part in 10{sup 9} or better) permits the effective elimination of audible and even sub-audible beats between the local (desired) station's carrier signal and the distant stations carriers, usually received via skywave propagation during the evening and nighttime hours. These carrier-beat components cause annoying modulations of the desired station's audio at the receiver and concurrent distortion of the audio modulation from the distant station(s) andmore » often cause listeners to ldquotune outrdquo due to the low reception quality. Significant reduction or elimination of the beats and related effects will greatly enlarge the effective (interference-limited) listening area of the desired station (from 4 to 10 times as indicated in our tests) and simultaneously reduce the corresponding interference of the local transmitter to the distant stations as well. In addition, AM stereo (CQUAM) reception will be particularly improved by minimizing the phase shifts induced by co-channel interfering signals; hybrid digital (HD) signals will also benefit via reduction in beats from analog signals. The automatic frequency-control hardware described is inexpensive ($1000-$2000), requires no periodic recalibration, has essentially zero long-term drift, and could employ alternate wide-area frequency references of suitable accuracy, including broadcasts from WWVB, LORAN-C, and equivalent sources. The basic configuration of the GPS-disciplined oscillator which solves this problem is extremely simple. The main oscillator is a conventional high-stability quartz-crystal type. To counter long- term drifts, the oscillator is slightly adjusted to track a high-precision source of standard frequency obtained from a specialized GPS receiver (or other source), usually at 10.000 MHz. This very stable local reference frequency is then used as a clock for a standard digitally implemented frequency synthesizer, which is programmed to generate the specific carrier frequency desired. The stability of the disciplining source, typically {approx}1 part in 10{sup 9} to 10{sup 11}, is thus transferred to the final AM transmitter carrier output frequency.« less

A Crystal-Physical Model of Electrotransfer in the Superionic Conductor Pb1 - x Sc x F2 + x ( x = 0.1)

NASA Astrophysics Data System (ADS)

Sorokin, N. I.

2018-04-01

The frequency (ν = 10-1-107 Hz) dependences of electrical conductivity σ(ν) of single crystals of superionic conductor Pb0.9Sc0.1F2.1 (10 mol % ScF3) with fluorite type structure (CaF2) in the temperature range 153-410 K have been investigated. The static bulk conductivity σ dc =1.5 × 10-4 S/cm and average hopping frequency ν h = 1.5 × 107 Hz of charge carriers (mobile ions F-) at room temperature (293 K) have been defined from the σ dc (ν) experimental curves. Enthalpies of thermoactivated processes of ionic conductivity σ dc ( T) (Δ H σ = 0.393 ± 0.005 eV) and dielectric relaxation ν h ( T) (Δ H h = 0.37 ± 0.03 eV) coincide within their errors. A crystal-physical model of fluorine-ion transport in a Pb0.9Sc0.1F2.1 crystal lattice has been proposed. The characteristic parameters of charge carriers have been calculated: concentration n mob = 2.0 × 1021 cm-3, the distance of the hopping d ≈ 0.5 nm and mobility μmob = 4.5 × 10-7 cm2/s V (293 K).

Moving target detection for frequency agility radar by sparse reconstruction

NASA Astrophysics Data System (ADS)

Quan, Yinghui; Li, YaChao; Wu, Yaojun; Ran, Lei; Xing, Mengdao; Liu, Mengqi

2016-09-01

Frequency agility radar, with randomly varied carrier frequency from pulse to pulse, exhibits superior performance compared to the conventional fixed carrier frequency pulse-Doppler radar against the electromagnetic interference. A novel moving target detection (MTD) method is proposed for the estimation of the target's velocity of frequency agility radar based on pulses within a coherent processing interval by using sparse reconstruction. Hardware implementation of orthogonal matching pursuit algorithm is executed on Xilinx Virtex-7 Field Programmable Gata Array (FPGA) to perform sparse optimization. Finally, a series of experiments are performed to evaluate the performance of proposed MTD method for frequency agility radar systems.

Moving target detection for frequency agility radar by sparse reconstruction.

PubMed

Quan, Yinghui; Li, YaChao; Wu, Yaojun; Ran, Lei; Xing, Mengdao; Liu, Mengqi

2016-09-01

Frequency agility radar, with randomly varied carrier frequency from pulse to pulse, exhibits superior performance compared to the conventional fixed carrier frequency pulse-Doppler radar against the electromagnetic interference. A novel moving target detection (MTD) method is proposed for the estimation of the target's velocity of frequency agility radar based on pulses within a coherent processing interval by using sparse reconstruction. Hardware implementation of orthogonal matching pursuit algorithm is executed on Xilinx Virtex-7 Field Programmable Gata Array (FPGA) to perform sparse optimization. Finally, a series of experiments are performed to evaluate the performance of proposed MTD method for frequency agility radar systems.

49 CFR 391.69 - Private motor carrier of passengers (business).

Code of Federal Regulations, 2010 CFR

2010-10-01

... MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY... road tests) do not apply to a driver who was a single-employer driver (as defined in § 390.5 of this...

49 CFR 391.69 - Private motor carrier of passengers (business).

Code of Federal Regulations, 2011 CFR

2011-10-01

... MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY... road tests) do not apply to a driver who was a single-employer driver (as defined in § 390.5 of this...

47 CFR 54.411 - Link Up program defined.

Code of Federal Regulations, 2010 CFR

2010-10-01

... section. (c) A carrier's Link Up program shall allow a consumer to receive the benefit of the Link Up... SERVICE Universal Service Support for Low-Income Consumers § 54.411 Link Up program defined. (a) For... low-income consumers, which an eligible telecommunications carrier shall offer as part of its...

Post Hoc Analyses of ApoE Genotype-Defined Subgroups in Clinical Trials.

PubMed

Kennedy, Richard E; Cutter, Gary R; Wang, Guoqiao; Schneider, Lon S

2016-01-01

Many post hoc analyses of clinical trials in Alzheimer's disease (AD) and mild cognitive impairment (MCI) are in small Phase 2 trials. Subject heterogeneity may lead to statistically significant post hoc results that cannot be replicated in larger follow-up studies. We investigated the extent of this problem using simulation studies mimicking current trial methods with post hoc analyses based on ApoE4 carrier status. We used a meta-database of 24 studies, including 3,574 subjects with mild AD and 1,171 subjects with MCI/prodromal AD, to simulate clinical trial scenarios. Post hoc analyses examined if rates of progression on the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog) differed between ApoE4 carriers and non-carriers. Across studies, ApoE4 carriers were younger and had lower baseline scores, greater rates of progression, and greater variability on the ADAS-cog. Up to 18% of post hoc analyses for 18-month trials in AD showed greater rates of progression for ApoE4 non-carriers that were statistically significant but unlikely to be confirmed in follow-up studies. The frequency of erroneous conclusions dropped below 3% with trials of 100 subjects per arm. In MCI, rates of statistically significant differences with greater progression in ApoE4 non-carriers remained below 3% unless sample sizes were below 25 subjects per arm. Statistically significant differences for ApoE4 in post hoc analyses often reflect heterogeneity among small samples rather than true differential effect among ApoE4 subtypes. Such analyses must be viewed cautiously. ApoE genotype should be incorporated into the design stage to minimize erroneous conclusions.

A high capacity data centre network: simultaneous 4-PAM data at 20 Gbps and 2 GHz phase modulated RF clock signal over a single VCSEL carrier

NASA Astrophysics Data System (ADS)

Isoe, G. M.; Wassin, S.; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

2017-11-01

Optical fibre communication technologies are playing important roles in data centre networks (DCNs). Techniques for increasing capacity and flexibility for the inter-rack/pod communications in data centres have drawn remarkable attention in recent years. In this work, we propose a low complexity, reliable, alternative technique for increasing DCN capacity and flexibility through multi-signal modulation onto a single mode VCSEL carrier. A 20 Gbps 4-PAM data signal is directly modulated on a single mode 10 GHz bandwidth VCSEL carrier at 1310 nm, therefore, doubling the network bit rate. Carrier spectral efficiency is further maximized by modulating its phase attribute with a 2 GHz reference frequency (RF) clock signal. We, therefore, simultaneously transmit a 20 Gbps 4-PAM data signal and a phase modulated 2 GHz RF signal using a single mode 10 GHz bandwidth VCSEL carrier. It is the first time a single mode 10 GHz bandwidth VCSEL carrier is reported to simultaneously transmit a directly modulated 4-PAM data signal and a phase modulated RF clock signal. A receiver sensitivity of -10. 52 dBm was attained for a 20 Gbps 4-PAM VCSEL transmission. The 2 GHz phase modulated RF clock signal introduced a power budget penalty of 0.21 dB. Simultaneous distribution of both data and timing signals over shared infrastructure significantly increases the aggregated data rate at different optical network units within the DCN, without expensive optics investment. We further demonstrate on the design of a software-defined digital signal processing assisted receiver to efficiently recover the transmitted signal without employing costly receiver hardware.

Controlling the high frequency response of H2 by ultra-short tailored laser pulses: A time-dependent configuration interaction study

NASA Astrophysics Data System (ADS)

Schönborn, Jan Boyke; Saalfrank, Peter; Klamroth, Tillmann

2016-01-01

We combine the stochastic pulse optimization (SPO) scheme with the time-dependent configuration interaction singles method in order to control the high frequency response of a simple molecular model system to a tailored femtosecond laser pulse. For this purpose, we use H2 treated in the fixed nuclei approximation. The SPO scheme, as similar genetic algorithms, is especially suited to control highly non-linear processes, which we consider here in the context of high harmonic generation. Here, we will demonstrate that SPO can be used to realize a "non-harmonic" response of H2 to a laser pulse. Specifically, we will show how adding low intensity side frequencies to the dominant carrier frequency of the laser pulse and stochastically optimizing their contribution can create a high-frequency spectral signal of significant intensity, not harmonic to the carrier frequency. At the same time, it is possible to suppress the harmonic signals in the same spectral region, although the carrier frequency is kept dominant during the optimization.

Controlling the high frequency response of H{sub 2} by ultra-short tailored laser pulses: A time-dependent configuration interaction study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schönborn, Jan Boyke; Saalfrank, Peter; Klamroth, Tillmann, E-mail: klamroth@uni-potsdam.de

2016-01-28

We combine the stochastic pulse optimization (SPO) scheme with the time-dependent configuration interaction singles method in order to control the high frequency response of a simple molecular model system to a tailored femtosecond laser pulse. For this purpose, we use H{sub 2} treated in the fixed nuclei approximation. The SPO scheme, as similar genetic algorithms, is especially suited to control highly non-linear processes, which we consider here in the context of high harmonic generation. Here, we will demonstrate that SPO can be used to realize a “non-harmonic” response of H{sub 2} to a laser pulse. Specifically, we will show howmore » adding low intensity side frequencies to the dominant carrier frequency of the laser pulse and stochastically optimizing their contribution can create a high-frequency spectral signal of significant intensity, not harmonic to the carrier frequency. At the same time, it is possible to suppress the harmonic signals in the same spectral region, although the carrier frequency is kept dominant during the optimization.« less

Improved MIMO radar GMTI via cyclic-shift transmission of orthogonal frequency division signals

NASA Astrophysics Data System (ADS)

Li, Fuyou; He, Feng; Dong, Zhen; Wu, Manqing

2018-05-01

Minimum detectable velocity (MDV) and maximum detectable velocity are both important in ground moving target indication (GMTI) systems. Smaller MDV can be achieved by longer baseline via multiple-input multiple-output (MIMO) radar. Maximum detectable velocity is decided by blind velocities associated with carrier frequencies, and blind velocities can be mitigated by orthogonal frequency division signals. However, the scattering echoes from different carrier frequencies are independent, which is not good for improving MDV performance. An improved cyclic-shift transmission is applied in MIMO GMTI system in this paper. MDV performance is improved due to the longer baseline, and maximum detectable velocity performance is improved due to the mitigation of blind velocities via multiple carrier frequencies. The signal model for this mode is established, the principle of mitigating blind velocities with orthogonal frequency division signals is presented; the performance of different MIMO GMTI waveforms is analysed; and the performance of different array configurations is analysed. Simulation results by space-time-frequency adaptive processing proves that our proposed method is a valid way to improve GMTI performance.

47 CFR 69.105 - Carrier common line for non-price cap local exchange carriers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Carrier common line for non-price cap local... for non-price cap local exchange carriers. (a) This section is applicable only to local exchange carriers that are not subject to price cap regulation as that term is defined in § 61.3(ee) of this chapter...

Tracking Architecture Based on Dual-Filter with State Feedback and Its Application in Ultra-Tight GPS/INS Integration

PubMed Central

Zhang, Xi; Miao, Lingjuan; Shao, Haijun

2016-01-01

If a Kalman Filter (KF) is applied to Global Positioning System (GPS) baseband signal preprocessing, the estimates of signal phase and frequency can have low variance, even in highly dynamic situations. This paper presents a novel preprocessing scheme based on a dual-filter structure. Compared with the traditional model utilizing a single KF, this structure avoids carrier tracking being subjected to code tracking errors. Meanwhile, as the loop filters are completely removed, state feedback values are adopted to generate local carrier and code. Although local carrier frequency has a wide fluctuation, the accuracy of Doppler shift estimation is improved. In the ultra-tight GPS/Inertial Navigation System (INS) integration, the carrier frequency derived from the external navigation information is not viewed as the local carrier frequency directly. That facilitates retaining the design principle of state feedback. However, under harsh conditions, the GPS outputs may still bear large errors which can destroy the estimation of INS errors. Thus, an innovative integrated navigation filter is constructed by modeling the non-negligible errors in the estimated Doppler shifts, to ensure INS is properly calibrated. Finally, field test and semi-physical simulation based on telemetered missile trajectory validate the effectiveness of methods proposed in this paper. PMID:27144570

Tracking Architecture Based on Dual-Filter with State Feedback and Its Application in Ultra-Tight GPS/INS Integration.

PubMed

Zhang, Xi; Miao, Lingjuan; Shao, Haijun

2016-05-02

If a Kalman Filter (KF) is applied to Global Positioning System (GPS) baseband signal preprocessing, the estimates of signal phase and frequency can have low variance, even in highly dynamic situations. This paper presents a novel preprocessing scheme based on a dual-filter structure. Compared with the traditional model utilizing a single KF, this structure avoids carrier tracking being subjected to code tracking errors. Meanwhile, as the loop filters are completely removed, state feedback values are adopted to generate local carrier and code. Although local carrier frequency has a wide fluctuation, the accuracy of Doppler shift estimation is improved. In the ultra-tight GPS/Inertial Navigation System (INS) integration, the carrier frequency derived from the external navigation information is not viewed as the local carrier frequency directly. That facilitates retaining the design principle of state feedback. However, under harsh conditions, the GPS outputs may still bear large errors which can destroy the estimation of INS errors. Thus, an innovative integrated navigation filter is constructed by modeling the non-negligible errors in the estimated Doppler shifts, to ensure INS is properly calibrated. Finally, field test and semi-physical simulation based on telemetered missile trajectory validate the effectiveness of methods proposed in this paper.

System for transmitting low frequency analog signals over AC power lines

DOEpatents

Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

1989-01-01

A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

System for transmitting low frequency analog signals over AC power lines

DOEpatents

Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

1989-09-05

A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

A system for tranmitting low frequency analog signals over ac power lines

DOEpatents

Baker, S.P.; Durall, R.L.; Haynes, H.D.

1987-07-30

A system for transmitting low frequency analog signals over ac power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an ac power line. The modulation signal frequency range is selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the ac power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal. 4 figs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Stephen F; Moore, James A

Systems and methods are described for carrier phase synchronization for improved AM and TV broadcast reception. A method includes synchronizing the phase of a carrier frequency of a broadcast signal with the phase of a remote reference frequency. An apparatus includes a receiver to detect the phase of a reference signal; a phase comparator coupled to the reference signal-phase receiver; a voltage controlled oscillator coupled to the phase comparator; and a phase-controlled radio frequency output coupled to the voltage controlled oscillator.

Both Hemophilia Health Care Providers and Hemophilia A Carriers Report that Carriers have Excessive Bleeding

PubMed Central

Paroskie, Allison; Oso, Olatunde; DeBaun, Michael R.; Sidonio, Robert F

2014-01-01

Introduction Hemophilia A, the result of reduced factor VIII (FVIII) activity, is an X-linked recessive bleeding disorder. Previous reports of Hemophilia A carriers suggest an increased bleeding tendency. Our objective was to determine the attitudes and understanding of the Hemophilia A carrier bleeding phenotype, and opinions regarding timing of carrier testing from the perspective of both medical providers and affected patients. Data from this survey was used as preliminary data for an ongoing prospective study. Material and Methods An electronic survey was distributed to physicians and nurses employed at Hemophilia Treatment Centers (HTC), and Hemophilia A carriers who were members of Hemophilia Federation of America. Questions focused on the clinical understanding of bleeding symptoms and management of Hemophilia A carriers, and the timing and intensity of carrier testing. Results Our survey indicates that 51% (36/51) of providers compared to 78% (36/46) of carriers believe that Hemophilia A carriers with normal FVIII activity have an increased bleeding tendency (p<0.001); 72% (33/36) of Hemophilia A carriers report a high frequency of bleeding symptoms. Regarding carrier testing, 72% (50/69) of medical providers recommend testing after 14 years of age, conversely 65% (29/45) of Hemophilia A carriers prefer testing to be done prior to this age (p<0.001). Discussion Hemophilia A carriers self-report a higher frequency of bleeding than previously acknowledged, and have a preference for earlier testing to confirm carrier status. PMID:24309601

47 CFR 101.705 - Special showing for renewal of common carrier station facilities using frequency diversity.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Special showing for renewal of common carrier... COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Common Carrier Fixed Point-to-Point Microwave Service § 101.705 Special showing for renewal of common carrier station...

POWER DENSITY, FIELD INTENSITY, AND CARRIER FREQUENCY DETERMINANTS OF RF-ENERGY-INDUCED CALCIUM-ION EFFLUX FROM BRAIN TISSUE

EPA Science Inventory

To explain a carrier frequency dependence reported for radiofrequency (RF)-induced calcium-ion efflux from brain tissue, a chick-brain hemisphere bathed in buffer solution is modeled as a sphere within the uniform field of the incident electromagnetic wave. Calculations on a sphe...

47 CFR 95.639 - Maximum transmitter power.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) No GMRS transmitter, under any condition of modulation, shall exceed: (1) 50 W Carrier power (average... transmitter, under any condition of modulation, shall exceed a carrier power or peak envelope TP (single-sideband only) of: (1) 4 W in the 26-27 MHz frequency band, except on channel frequency 27.255 MHz; (2) 25...

47 CFR 101.705 - Special showing for renewal of common carrier station facilities using frequency diversity.

Code of Federal Regulations, 2014 CFR

2014-10-01

... COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Common Carrier Fixed Point-to-Point Microwave Service § 101.705 Special showing for renewal of common carrier station...

47 CFR 101.705 - Special showing for renewal of common carrier station facilities using frequency diversity.

Code of Federal Regulations, 2013 CFR

2013-10-01

... COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Common Carrier Fixed Point-to-Point Microwave Service § 101.705 Special showing for renewal of common carrier station...

47 CFR 101.705 - Special showing for renewal of common carrier station facilities using frequency diversity.

Code of Federal Regulations, 2012 CFR

2012-10-01

... COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Common Carrier Fixed Point-to-Point Microwave Service § 101.705 Special showing for renewal of common carrier station...

47 CFR 101.705 - Special showing for renewal of common carrier station facilities using frequency diversity.

Code of Federal Regulations, 2011 CFR

2011-10-01

... COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Common Carrier Fixed Point-to-Point Microwave Service § 101.705 Special showing for renewal of common carrier station...

A model for phase noise generation in amplifiers.

PubMed

Tomlin, T D; Fynn, K; Cantoni, A

2001-11-01

In this paper, a model is presented for predicting the phase modulation (PM) and amplitude modulation (AM) noise in bipolar junction transistor (BJT) amplifiers. The model correctly predicts the dependence of phase noise on the signal frequency (at a particular carrier offset frequency), explains the noise shaping of the phase noise about the signal frequency, and shows the functional dependence on the transistor parameters and the circuit parameters. Experimental studies on common emitter (CE) amplifiers have been used to validate the PM noise model at carrier frequencies between 10 and 100 MHz.

Self Consistent Ambipolar Transport and High Frequency Oscillatory Transient in Graphene Electronics

DTIC Science & Technology

2015-08-17

study showed that in the presence of an ac field, THz oscillations exhibit soft resonances at a frequency roughly equal to half of the inverse of the ...exhibit soft resonances at a frequency roughly equal to half of the inverse of the carrier transit time to the LO phonon energy. It also showed that in...carriers in graphene undergo an anomalous parametric resonance. Such resonance occurs at about half the frequency ωF = 2πeF/~ωOP , where 2π/ωF is the time

Spectral context affects temporal processing in awake auditory cortex

PubMed Central

Beitel, Ralph E.; Vollmer, Maike; Heiser, Marc A; Schreiner, Christoph E.

2013-01-01

Amplitude modulation encoding is critical for human speech perception and complex sound processing in general. The modulation transfer function (MTF) is a staple of auditory psychophysics, and has been shown to predict speech intelligibility performance in a range of adverse listening conditions and hearing impairments, including cochlear implant-supported hearing. Although both tonal and broadband carriers have been employed in psychophysical studies of modulation detection and discrimination, relatively little is known about differences in the cortical representation of such signals. We obtained MTFs in response to sinusoidal amplitude modulation (SAM) for both narrowband tonal carriers and 2-octave bandwidth noise carriers in the auditory core of awake squirrel monkeys. MTFs spanning modulation frequencies from 4 to 512 Hz were obtained using 16 channel linear recording arrays sampling across all cortical laminae. Carrier frequency for tonal SAM and center frequency for noise SAM was set at the estimated best frequency for each penetration. Changes in carrier type affected both rate and temporal MTFs in many neurons. Using spike discrimination techniques, we found that discrimination of modulation frequency was significantly better for tonal SAM than for noise SAM, though the differences were modest at the population level. Moreover, spike trains elicited by tonal and noise SAM could be readily discriminated in most cases. Collectively, our results reveal remarkable sensitivity to the spectral content of modulated signals, and indicate substantial interdependence between temporal and spectral processing in neurons of the core auditory cortex. PMID:23719811

Variants of transcription factor 7-like 2 (TCF7L2) gene and incident glucose intolerance in Japanese-Brazilians.

PubMed

Franco, L F; Crispim, F; Pereira, A C; Moisés, R S

2011-03-01

Common variants of the transcription factor 7-like 2 (TCF7L2) gene have been found to be associated with type 2 diabetes in different ethnic groups. The Japanese-Brazilian population has one of the highest prevalence rates of diabetes. Therefore, the aim of the present study was to assess whether two single-nucleotide polymorphisms (SNPs) of TCF7L2, rs7903146 and rs12255372, could predict the development of glucose intolerance in Japanese-Brazilians. In a population-based 7-year prospective study, we genotyped 222 individuals (72 males and 150 females, aged 56.2 ± 10.5 years) with normal glucose tolerance at baseline. In the study population, we found that the minor allele frequency was 0.05 for SNP rs7903146 and 0.03 for SNP rs12255372. No significant allele or genotype association with glucose intolerance incidence was found for either SNP. Haplotypes were constructed with these two SNPs and three haplotypes were defined: CG (frequency: 0.94), TT (frequency = 0.027) and TG (frequency = 0.026). None of the haplotypes provided evidence for association with the incidence of glucose intolerance. Despite no associations between incidence of glucose intolerance and SNPs of the TCF7L2 gene in Japanese-Brazilians, we found that carriers of the CT genotype for rs7903146 had significantly lower insulin levels 2 h after a 75-g glucose load than carriers of the CC genotype. In conclusion, in Japanese-Brazilians, a population with a high prevalence of type 2 diabetes, common TCF7L2 variants did not make major contributions to the incidence of glucose tolerance abnormalities.

Leu7Pro polymorphism of PreproNPY associated with an increased risk for type II diabetes in middle-aged subjects.

PubMed

Ukkola, O; Kesäniemi, Y A

2007-09-01

Neuropeptide Y (NPY) plays a central in energy homeostasis and potentially in the development of obesity-related comorbidities, like type II diabetes. As the PreproNPY Leu7Pro polymorphism probably changes the intracellular processing of the synthesized preproNPY peptide, we assessed the hypothesis that PreproNPY Leu7Pro polymorphism is a risk factor for type II diabetes, impaired glucose tolerance and hypertension. Blood pressure recordings and oral glucose tolerance test were performed in the hypertensive (n=515) and control cohorts (n=525) of our well-defined Oulu Project Elucidating Risk of Atherosclerosis (OPERA) study. The prevalence of type II diabetes was 9% (n=93). The genotypes, insulin and glucose metabolism indexes and plasma ghrelin of the subjects were determined. Pro7 allele frequencies were 5.9, 5.3 and 11.3% in the total cohort, in subjects without and with type II diabetes, respectively. The PreproNPY Pro7 carrier status was a significant risk factor for type II diabetes, and the effect remained significant after adjustment for age, sex, waist circumference and study group (odds ratio=3.02, confidence interval: 1.67-5.44 and P<0.001). Pro7 carriers were more insulin resistant and showed lower ghrelin levels compared to non-carriers. The PreproNPY Pro7 allele is associated with an increased risk for type II diabetes. The risk seems to be associated with a higher insulin resistance among Pro7 carriers whereas low ghrelin concentrations in Pro7 carriers are possibly a consequence of high insulin levels.

An Exploration of Software-Based GNSS Signal Processing at Multiple Frequencies

NASA Astrophysics Data System (ADS)

Pasqual Paul, Manuel; Elosegui, Pedro; Lind, Frank; Vazquez, Antonio; Pankratius, Victor

2017-01-01

The Global Navigation Satellite System (GNSS; i.e., GPS, GLONASS, Galileo, and other constellations) has recently grown into numerous areas that go far beyond the traditional scope in navigation. In the geosciences, for example, high-precision GPS has become a powerful tool for a myriad of geophysical applications such as in geodynamics, seismology, paleoclimate, cryosphere, and remote sensing of the atmosphere. Positioning with millimeter-level accuracy can be achieved through carrier-phase-based, multi-frequency signal processing, which mitigates various biases and error sources such as those arising from ionospheric effects. Today, however, most receivers with multi-frequency capabilities are highly specialized hardware receiving systems with proprietary and closed designs, limited interfaces, and significant acquisition costs. This work explores alternatives that are entirely software-based, using Software-Defined Radio (SDR) receivers as a way to digitize the entire spectrum of interest. It presents an overview of existing open-source frameworks and outlines the next steps towards converting GPS software receivers from single-frequency to dual-frequency, geodetic-quality systems. In the future, this development will lead to a more flexible multi-constellation GNSS processing architecture that can be easily reused in different contexts, as well as to further miniaturization of receivers.

47 CFR 1.1402 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Procedures § 1.1402 Definitions. (a) The term utility means any person that is a local exchange carrier or an electric, gas, water, steam, or other public utility, and who owns or controls poles, ducts, conduits, or... telecommunications services (as defined in 47 U.S.C. 226) or incumbent local exchange carriers (as defined in 47 U.S...

PWM Switching Frequency Effects on Eddy Current Sensors for Magnetically Suspended Flywheel Systems

NASA Technical Reports Server (NTRS)

Jansen, Ralph; Lebron, Ramon; Dever, Timothy P.; Birchenough, Arthur G.

2003-01-01

A flywheel magnetic bearing (MB) pulse width modulated power amplifier (PWM) configuration is selected to minimize noise generated by the PWMs in the flywheel position sensor system. Two types of noise are addressed: beat frequency noise caused by variations in PWM switching frequencies, and demodulation noise caused by demodulation of high order harmonics of the switching voltage into the MB control band. Beat frequency noise is eliminated by synchronizing the PWM switch frequencies, and demodulation noise is minimized by selection of a switching frequency which does not have harmonics at the carrier frequency of the sensor. The recommended MB PWM system has five synchronized PWMs switching at a non-integer harmonic of the sensor carrier.

Demodulation of OFDM Signals in the Presence of Deep Fading Channels and Signal Clipping

DTIC Science & Technology

2012-06-01

2Re Cj F ts t e x tπ= (1) where CF is the carrier frequency. The complex baseband signal is subdivided into time intervals of length...SymbolT . Within the -thm time interval the signal ( )x t is defined as ( ) 2 2 2 0 ( ) 0< F F Nk j k Ft Symbol m k Symbol Nk k x mT t x t c e t Tπ...is the symbol length and consists of the guard interval gT and data interval bT : .Symbol g bT T T = + (3) In order to guarantee the subcarriers

Increased cancer risk of heterozygotes with NBS1 germline mutations in Poland.

PubMed

Steffen, Jan; Varon, Raymonda; Mosor, Maria; Maneva, Galina; Maurer, Martin; Stumm, Markus; Nowakowska, Dorota; Rubach, Maryna; Kosakowska, Ewa; Ruka, Włodzimierz; Nowecki, Zbigniew; Rutkowski, Piotr; Demkow, Tomasz; Sadowska, Małgorzata; Bidziński, Mariusz; Gawrychowski, Krzysztof; Sperling, Karl

2004-08-10

It has been suggested based on familial data that Nijmegen breakage syndrome (NBS) heterozygotes have an increased risk of malignant tumors. We found 15 carriers of the 657del5 mutation and 8 carriers of the R215W molecular variant of the NBS1 gene among 1,289 consecutive patients from Central Poland with various cancers and only 10 and 4 such carriers, respectively, in 1,620 controls from this region. Most of the 657del5 mutation carriers were found among patients with melanoma (4/105), non-Hodgkin lymphoma (2/42) and breast cancer (4/224) and of the 234 patients with colorectal carcinoma 3 carried the 657del5 mutation and 3 others the R215W molecular variant. The frequencies of 657del5 mutation carriers among patients with melanoma and non-Hodgkin lymphoma and of R215W carriers in patients with colorectal cancer were significantly higher than in controls (p < 0.01, < 0.05 and < 0.05 respectively). The pooled frequencies of 657del5 and R215W mutations in all cancer patients were also significantly higher than in controls (p < 0.05). Two carriers of the 657del5 mutation had second primary tumors. Malignant tumors among parents and siblings of 657del5 mutation carriers (14/77) were twice more frequent than in population controls. Three carriers of this mutation (2 probands with melanoma) reported melanoma in relatives. These results suggest strongly that NBS1 heterozygosity may be associated with elevated risk of some cancers. Larger studies are needed to evaluate the impact of the high frequency of germline NBS1 mutations on the cancer burden in the Slav populations. Copyright 2004 Wiley-Liss, Inc.

Long distance measurement with a femtosecond laser based frequency comb

NASA Astrophysics Data System (ADS)

Bhattacharya, N.; Cui, M.; Zeitouny, M. G.; Urbach, H. P.; van den Berg, S. A.

2017-11-01

Recent advances in the field of ultra-short pulse lasers have led to the development of reliable sources of carrier envelope phase stabilized femtosecond pulses. The pulse train generated by such a source has a frequency spectrum that consists of discrete, regularly spaced lines known as a frequency comb. In this case both the frequency repetition and the carrier-envelope-offset frequency are referenced to a frequency standard, like an atomic clock. As a result the accuracy of the frequency standard is transferred to the optical domain, with the frequency comb as transfer oscillator. These unique properties allow the frequency comb to be applied as a versatile tool, not only for time and frequency metrology, but also in fundamental physics, high-precision spectroscopy, and laser noise characterization. The pulse-to-pulse phase relationship of the light emitted by the frequency comb has opened up new directions for long range highly accurate distance measurement.

Associated Clinical Disorders Diagnosed by Medical Specialists in 188 FMR1 Premutation Carriers Found in the Last 25 Years in the Spanish Basque Country: A Retrospective Study

PubMed Central

Merino, Sonia; Ibarluzea, Nekane; Maortua, Hiart; Prieto, Begoña; Rouco, Idoia; López-Aríztegui, Maria-Asunción; Tejada, Maria-Isabel

2016-01-01

Fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X-associated primary ovarian insufficiency (FXPOI) are definitely related to the fragile X mental retardation 1 (FMR1) premutation (PM). Additional medical problems have also been associated with the PM, such as fibromyalgia, endocrine, and psychiatric disorders. To improve our understanding in the field, we reviewed all PM carriers and their reasons for any medical referrals from 104 fragile X families molecularly diagnosed in our laboratory and living in the Spanish Basque Country. After signing the written informed consent, we studied their electronic medical records in order to identify the disorders associated with the PM and their frequencies. We obtained clinical data in 188 PM carriers (147 women and 41 men). In women, the frequency of FXPOI (22.61%) was similar to that previously reported in PM carriers. In men, the frequency of definite FXTAS (28.57%) was lower than reported elsewhere. Furthermore, thyroid pathology was associated with the PM, the frequency of hypothyroidism being much higher in the studied region than in the general population (8.84% vs. 0.93%). Finally, we found no association with fibromyalgia or psychiatric problems. These findings represent another population contribution in this field and may be useful for the clinical management of PM carriers. PMID:27775646

Multiplexing of Radio-Frequency Single Electron Transistors

NASA Technical Reports Server (NTRS)

Stevenson, Thomas R.; Pellerano, F. A.; Stahle, C. M.; Aidala, K.; Schoelkopf, R. J.; Krebs, Carolyn (Technical Monitor)

2001-01-01

We present results on wavelength division multiplexing of radio-frequency single electron transistors. We use a network of resonant impedance matching circuits to direct applied rf carrier waves to different transistors depending on carrier frequency. A two-channel demonstration of this concept using discrete components successfully reconstructed input signals with small levels of cross coupling. A lithographic version of the rf circuits had measured parameters in agreement with electromagnetic modeling, with reduced cross capacitance and inductance, and should allow 20 to 50 channels to be multiplexed.

Polaron formation in normal state optical conductivity of iron-based superconductor

NASA Astrophysics Data System (ADS)

Choudhary, K. K.; Lodhi, Pavitra Devi; Kaurav, Netram

2018-05-01

Normal state Optical conductivity σ(ω) of Iron-Based superconductor LaFeAsO have been investigated using polaron formation mechanism. The coherent Drude free carrier excitations as well as the incoherent motion of carriers leading to a polaron formation, originated from inter and intra layer transitions of charge carriers are incorporated in the present model. Coherent motion of Drude carriers obtained from an effective interaction potential leads to a peak at zero frequency regime which is an indication of metallic conduction in superconducting materials and also produces a long tail at higher frequencies infrared region. Whereas, the incoherent motion i.e. hopping of carriers from Fe to Fe in the FeAs layer and from FeAs layer to LaO layer produces two different peaks at around 100 cm-1 and 430 cm-1 respectively. Two contributions, Drude and hopping carriers successfully explain the anomalies observed in the optical conductivity of metallic state of the iron-based superconductors.

Suppression of Rayleigh backscattering noise using cascaded-SOA and microwave photonic filter for 10 Gb/s loop-back WDM-PON.

PubMed

Feng, Hanlin; Ge, Jia; Xiao, Shilin; Fok, Mable P

2014-05-19

In this paper, we present a novel Rayleigh backscattering (RB) noise mitigation scheme based on central carrier suppression for 10 Gb/s loop-back wavelength division multiplexing passive optical network (WDM-PON). Microwave modulated multi-subcarrier optical signal is used as downstream seeding light, while cascaded semiconductor optical amplifier (SOA) are used in the optical network unit (ONU) for suppressing the central carrier of the multi-subcarrier upstream signal. With central carrier suppression, interference generated by carrier RB noise at low frequency region is eliminated successfully. Transmission performance over 45 km single mode fiber (SMF) is studied experimentally, and the optical-signal-to-Rayleigh-noise-ratio (OSRNR) can be reduced to 15 dB with central carrier suppression ratio (CCSR) of 21 dB. Receiver sensitivity is further improved by 6 dB with the use of microwave photonic filter (MPF) for suppressing residual upstream microwave signal and residual carrier RB at high frequency region.

A universal array-based multiplexed test for cystic fibrosis carrier screening.

PubMed

Amos, Jean A; Bridge-Cook, Philippa; Ponek, Victor; Jarvis, Michael R

2006-01-01

Cystic fibrosis is a multisystem autosomal recessive disorder with high carrier frequencies in caucasians and significant, but lower, carrier frequencies in other ethnicities. Based on technology that allows high detection of mutations in caucasians and significant detection in other ethnic groups, the American College of Medical Genetics (ACMG) and American College of Obstetricians and Gynecologists (ACOG) have recommended pan-ethnic cystic fibrosis carrier screening for all reproductive couples. This paper discusses carrier screening using the Tag-It multiplex mutation platform and the Cystic Fibrosis Mutation Detection Kit. The Tag-It cystic fibrosis assay is a multiplexed genotyping assay that detects a panel of 40 cystic fibrosis transmembrane conductance regulator mutations including the 23 mutations recommended by the ACMG and ACOG for population screening. A total of 16 additional mutations detected by the Tag-It cystic fibrosis assay may also be common. The assay method is described in detail, and its performance in a genetics reference laboratory performing high-volume cystic fibrosis carrier screening is assessed.

Assessment of RF radiation levels in the vicinity of 60 GSM mobile phone base stations in Iran.

PubMed

Nayyeri, Vahid; Hashemi, Seyed Mohammad; Borna, Maryam; Jalilian, Hamid-Reza; Soleimani, Mohammad

2013-07-01

Increasing development of mobile communication infrastructure while enhancing availability of the technology raises concerns among the public, who see more cell towers erected each day, about possible health effects of electromagnetic radiations. Thereon, a survey of radio-frequency radiation from 60 GSM base stations was carried out in Tehran, Iran at several places mostly located in major medical and educational centres. Measurements were performed at 15 locations near each base station site, i.e. 900 locations in total. Since there are other RF radiation sources such as broadcasting services whose carrier frequencies are <3 GHz, the whole band of 27 MHz to 3 GHz has been assessed for hazardous exposures as well. The results were compared with the relevant guideline of International Commission on Non-Ionising Radiation Protection and that of Iran, confirming radiation exposure levels being satisfactorily below defined limits and non-detrimental.

Femtosecond study of A1g phonons in the strong 3D topological insulators: From pump-probe to coherent control

NASA Astrophysics Data System (ADS)

Hu, Jianbo; Igarashi, Kyushiro; Sasagawa, Takao; Nakamura, Kazutaka G.; Misochko, Oleg V.

2018-01-01

Fully symmetric A1g phonons are expected to play a dominant role in electron scattering in strong topological insulators (TIs), thus limiting the ballistic transport of future electronic devices. Here, we report on femtosecond time-resolved observation of a pair of A1g coherent phonons and their optical control in two strong 3D TIs, Bi2Te3 and Bi2Se3, by using a second pump pulse in ultrafast spectroscopy measurements. Along with well-defined phonon properties such as frequency and lifetime, an obvious phonon chirp has been observed, implying a strong coupling between photo-carriers and lattices. The coherent phonon manipulation, on the other hand, allows us to change the phonon amplitude selectively but does not affect either the frequency or coherence lifetime of the chosen mode.

Carrier-phase two-way satellite frequency transfer over a very long baseline

NASA Astrophysics Data System (ADS)

Fujieda, M.; Piester, D.; Gotoh, T.; Becker, J.; Aida, M.; Bauch, A.

2014-06-01

In this paper we report that carrier-phase two-way satellite time and frequency transfer (TWSTFT) was successfully demonstrated over a very long baseline of 9000 km, established between the National Institute of Information and Communications Technology (NICT) and the Physikalisch-Technische Bundesanstalt (PTB). We verified that the carrier-phase TWSTFT (TWCP) result agreed with those obtained by conventional TWSTFT and GPS carrier-phase (GPSCP) techniques. Moreover, a much improved short-term instability for frequency transfer of 2 × 10-13 at 1 s was achieved, which is at the same level as previously confirmed over a shorter baseline within Japan. The precision achieved was so high that the effects of ionospheric delay became significant; they are ignored in conventional TWSTFT even over a long link. We compensated for these effects using ionospheric delays computed from regional vertical total electron content maps. The agreement between the TWCP and GPSCP results was improved because of this compensation.

The Realization and Analysis of Capacitance Self Tracing (CST) Method for Wide Band Response Measurement of Carrier Type Dynamic Strain Amplifier

NASA Astrophysics Data System (ADS)

Kubodera, Shinji; Tanzawa, Tsutomu; Morisawa, Masayuki; Kiyohiro, Noriaki

Carrier type dynamic strain amplifiers are frequently used for stress measurement with strain gages. That is because the carrier type dynamic strain amplifier can conduct high precision measurement since it is highly resistant against hum noise from the power supply frequency in principle and is free from the thermoelectomotive force even if a metal contact is used in wiring to a Wheatstone bridge for measuring. A problem of the carrier type dynamic strain amplifier is generation of Capacitive component (hereinafter referred to as the C component) in an input cable connecting from the amplifier to the input sensor (Wheatstone bridge for measuring). The C component varies with cable length, cable materials, or ambient temperature change. The aforementioned changing adversely affects the stability of the amplifier. In this paper, we realize and analyze the method that increases the stability of amplifier by detecting, eliminating and self tracking the above C component constantly. Used carrier frequency at 12kHz and 28kHz. We made amplifiers with noise resistant and wide band frequency of measurement range and verified the theory of the Capacitance Self Tracing with the above amplifiers.

Amplitude modulation detection by human listeners in reverberant sound fields: Carrier bandwidth effects and binaural versus monaural comparison.

PubMed

Zahorik, Pavel; Kim, Duck O; Kuwada, Shigeyuki; Anderson, Paul W; Brandewie, Eugene; Collecchia, Regina; Srinivasan, Nirmal

2012-06-01

Previous work [Zahorik et al., POMA, 12, 050005 (2011)] has reported that for a broadband noise carrier signal in a simulated reverberant sound field, human sensitivity to amplitude modulation (AM) is higher than would be predicted based on the broadband acoustical modulation transfer function (MTF) of the listening environment. Interpretation of this result was complicated by the fact that acoustical MTFs of rooms are often quite different for different carrier frequency regions, and listeners may have selectively responded to advantageous carrier frequency regions where the effective acoustic modulation loss due to the room was less than indicated by a broadband acoustic MTF analysis. Here, AM sensitivity testing and acoustic MTF analyses were expanded to include narrowband noise carriers (1-octave and 1/3-octave bands centered at 4 kHz), as well as monaural and binaural listening conditions. Narrowband results were found to be consistent with broadband results: In a reverberant sound field, human AM sensitivity is higher than indicated by the acoustical MTFs. The effect was greatest for modulation frequencies above 32 Hz and was present whether the stimulation was monaural or binaural. These results are suggestive of mechanisms that functionally enhance modulation in reverberant listening.

Optical injection locking-based amplification in phase-coherent transfer of optical frequencies.

PubMed

Kim, Joonyoung; Schnatz, Harald; Wu, David S; Marra, Giuseppe; Richardson, David J; Slavík, Radan

2015-09-15

We demonstrate the use of an optical injection phase locked loop (OIPLL) as a regenerative amplifier for optical frequency transfer applications. The optical injection locking provides high gain within a narrow bandwidth (<100  MHz) and is capable of preserving the fractional frequency stability of the incoming carrier to better than 10(-18) at 1000 s. The OIPLL was tested in the field as a mid-span amplifier for the transfer of an ultrastable optical carrier, stabilized to an optical frequency standard, over a 292 km long installed dark fiber link. The transferred frequency at the remote end reached a fractional frequency instability of less than 1×10(-19) at averaging time of 3200 s.

Comparison of CYP2C9, CYP2C19, CYP2D6, ABCB1, and SLCO1B1 gene-polymorphism frequency in Russian and Nanai populations

PubMed Central

Sychev, Dmitrij Alekseevitch; Shuev, Grigorij Nikolaevich; Suleymanov, Salavat Shejhovich; Ryzhikova, Kristina Anatol’evna; Mirzaev, Karin Badavievich; Grishina, Elena Anatol’evna; Snalina, Natalia Evgenievna; Sozaeva, Zhannet Alimovna; Grabuzdov, Anton Mikhailovich; Matsneva, Irina Andreevna

2017-01-01

Background The efficiency and safety of drug therapy depends on the peculiarities of functioning of the P450 cytochrome group and transporting proteins. There are significant differences for single-nucleotide polymorphism (SNP) frequency. Materials and methods We studied the peculiarities of P450 cytochrome polymorphisms, SLCO1B1 transporting protein, and P-glycoprotein carriage in healthy volunteers in the Nanai ethnic group living in Russia, and compared them to the carriage of SNPs in the Russian population according to literature data. Results After performing the real-time polymerase chain reactions on the samples from 70 healthy volunteers from the Nanai group, for the CYP2C9*2C430T polymorphism we determined 70 CC-genotype carriers. As for the CYP2C9*3A1075C polymorphism, we found 62 AA-genotype carriers and eight AC-genotype carriers. For the CYP2C19*2G681A polymorphism, we determined 39 GG-genotype carriers and 28 GA-genotype carriers, for the CYP2C19*3G636A polymorphism 58 GG-genotype carriers and 12 GA-genotype carriers, and for the CYP2C19*17C806T polymorphism 67 CC-genotype carriers and three CT-genotype carriers. For the CYP2D6*4G1846A polymorphism, the GG genotype had 68 carriers, and the GA genotype two carriers. For the ABCB1*6C3435T polymorphism, there were 19 CC-genotype carriers and 39 CT-genotype carriers. For the SLCO1B1*5T521C polymorphism, the TT genotype had 41 carriers and the CT genotype 25 carriers. The distribution of genotypes fitted the Hardy–Weinberg equilibrium for all the polymorphisms, except those of CYP2C9*2. There were also significant differences in allele frequencies for some polymorphisms between the Nanais and the Russians. Conclusion In the Nanai population, there are polymorphisms connected with the decrease in safety and efficiency of drug therapy. Studying the ethnic differences might influence the determination of priority in the introduction of pharmacogenetic tests in clinical practice in different regions of Russia. PMID:28435307

14 CFR 330.3 - What do the terms used in this part mean?

Code of Federal Regulations, 2010 CFR

2010-01-01

... (AVIATION PROCEEDINGS) PROCEDURAL REGULATIONS PROCEDURES FOR COMPENSATION OF AIR CARRIERS General Provisions § 330.3 What do the terms used in this part mean? The following terms apply to this part: Air carrier means any U.S. air carrier, as defined in 49 U.S.C. 40102. Air taxi operator means an air carrier, other...

Carrier-envelope offset frequency stabilization of an ultrafast semiconductor laser

NASA Astrophysics Data System (ADS)

Jornod, Nayara; Gürel, Kutan; Wittwer, Valentin J.; Brochard, Pierre; Hakobyan, Sargis; Schilt, Stéphane; Waldburger, Dominik; Keller, Ursula; Südmeyer, Thomas

2018-02-01

We present the self-referenced stabilization of the carrier-envelope offset (CEO) frequency of a semiconductor disk laser. The laser is a SESAM-modelocked VECSEL emitting at a wavelength of 1034 nm with a repetition frequency of 1.8 GHz. The 270-fs pulses are amplified to 3 W and compressed to 120 fs for the generation of a coherent octavespanning supercontinuum spectrum. A quasi-common-path f-to-2f interferometer enables the detection of the CEO beat with a signal-to-noise ratio of 30 dB sufficient for its frequency stabilization. The CEO frequency is phase-locked to an external reference with a feedback signal applied to the pump current.

A Novel Photonic Clock and Carrier Recovery Device

NASA Technical Reports Server (NTRS)

Yao, X. Steve; Lutes, George; Maleki, Lute

1996-01-01

As data communication rates climb toward ten Gb/s, clock recovery and synchronization become more difficult, if not impossible, using conventional electronic circuits. We present in this article experimental results of a high speed clock and carrier recovery using a novel device called a photonic oscillator that we recently developed in our laboratory. This device is capable of recovering clock signals up to 70 GHz. To recover the clock, the incoming data is injected into the photonic oscillator either through the optical injection port or the electrical injection port. The free running photonic oscillator is tuned to oscillate at a nominal frequency equal to the clock frequency of the incoming data. With the injection of the data, the photonic oscillator will be quickly locked to clock frequency of the data stream while rejecting other frequency components associated with the data. Consequently, the output of the locked photonic oscillator is a continuous periodical wave synchronized with the incoming data or simply the recovered clock. We have demonstrated a clock to spur ratio of more than 60 dB of the recovered clock using this technique. Similar to the clock recovery, the photonic oscillator can be used to recover a high frequency carrier degraded by noise and an improvement of about 50 dB in signal-to-noise ratio was demonstrated. The photonic oscillator has both electrical and optical inputs and outputs and can be directly interfaced with a photonic system without signal conversion. In addition to clock and carrier recovery, the photonic oscillator can also be used for (1) stable high frequency clock signal generation, (2) frequency multiplication, (3) square wave and comb frequency generation, and (4) photonic phase locked loop.

Carrier Estimation Using Classic Spectral Estimation Techniques for the Proposed Demand Assignment Multiple Access Service

NASA Technical Reports Server (NTRS)

Scaife, Bradley James

1999-01-01

In any satellite communication, the Doppler shift associated with the satellite's position and velocity must be calculated in order to determine the carrier frequency. If the satellite state vector is unknown then some estimate must be formed of the Doppler-shifted carrier frequency. One elementary technique is to examine the signal spectrum and base the estimate on the dominant spectral component. If, however, the carrier is spread (as in most satellite communications) this technique may fail unless the chip rate-to-data rate ratio (processing gain) associated with the carrier is small. In this case, there may be enough spectral energy to allow peak detection against a noise background. In this thesis, we present a method to estimate the frequency (without knowledge of the Doppler shift) of a spread-spectrum carrier assuming a small processing gain and binary-phase shift keying (BPSK) modulation. Our method relies on an averaged discrete Fourier transform along with peak detection on spectral match filtered data. We provide theory and simulation results indicating the accuracy of this method. In addition, we will describe an all-digital hardware design based around a Motorola DSP56303 and high-speed A/D which implements this technique in real-time. The hardware design is to be used in NMSU's implementation of NASA's demand assignment, multiple access (DAMA) service.

Incidence and Carrier Frequency of CFTR Gene Mutations in Pregnancies With Echogenic Bowel in Nova Scotia and Prince Edward Island.

PubMed

Miller, Michelle E; Allen, Victoria M; Brock, Jo-Ann K

2018-03-01

Fetal echogenic bowel (echogenic bowel) is associated with cystic fibrosis (CF), with a reported incidence ranging from 1% to 13%. Prenatal testing for CF in the setting of echogenic bowel can be done by screening parental or fetal samples for pathogenic CFTR variants. If only one pathogenic variant is identified, sequencing of the CFTR gene can be undertaken, to identify a second pathogenic variant not covered in the standard screening panel. Full gene sequencing, however, also introduces the potential to identify variants of uncertain significance (VUSs) that can create counselling challenges and cause parental anxiety. To provide accurate counselling for families in the study population, the incidence of CF associated with echogenic bowel and the carrier frequency of CFTR variants were investigated. All pregnancies for which CF testing was undertaken for the indication of echogenic bowel (from Nova Scotia and Prince Edward Island) were identified (January 2007-July 2017). The CFTR screening and sequencing results were reviewed, and fetal outcomes related to CF were assessed. A total of 463 pregnancies with echogenic bowel were tested. Four were confirmed to be affected with CF, giving an incidence of 0.9% in this cohort. The carrier frequency of CF among all parents in the cohort was 5.0% (1 in 20); however, when excluding parents of affected fetuses, the carrier frequency for the population was estimated at 4.1% (1 in 25). CFTR gene sequencing identified an additional VUS in two samples. The incidence of CF in pregnancies with echogenic bowel in Nova Scotia and Prince Edward Island is 0.9%, with an estimated population carrier frequency of 4.1%. These results provide the basis for improved counselling to assess the risk of CF in the pregnancy, after parental carrier screening, using Bayesian probability. Counselling regarding VUSs should be undertaken before gene sequencing. Copyright © 2017 Society of Obstetricians and Gynaecologists of Canada. Published by Elsevier Inc. All rights reserved.

Differential effects of severe vs mild GBA mutations on Parkinson disease.

PubMed

Gan-Or, Ziv; Amshalom, Idan; Kilarski, Laura L; Bar-Shira, Anat; Gana-Weisz, Mali; Mirelman, Anat; Marder, Karen; Bressman, Susan; Giladi, Nir; Orr-Urtreger, Avi

2015-03-03

To better define the genotype-phenotype correlations between the type of GBA (glucosidase, beta, acid) mutation, severe or mild, and the risk and age at onset (AAO), and potential mechanism of Parkinson disease (PD). We analyzed 1,000 patients of Ashkenazi-Jewish descent with PD for 7 founder GBA mutations, and conducted a meta-analysis of risk and AAO according to GBA genotype (severe or mild mutation). The meta-analysis included 11,453 patients with PD and 14,565 controls from worldwide populations. The statistical analysis was done with and without continuity correction (constant or empirical), considering biases that could potentially affect the results. Among Ashkenazi-Jewish patients with PD, the odds ratios for PD were 2.2 and 10.3 for mild and severe GBA mutation carriers, respectively. The observed frequency of severe GBA mutation carriers among patients with PD was more than 4-fold than expected (4.4% vs 0.9%, respectively, p < 0.0001, Fisher exact test). In the different models of the meta-analysis, the odds ratios for PD ranged between 2.84 and 4.94 for mild GBA mutation carriers and 9.92 and 21.29 for severe GBA mutation carriers (p < 1 × 10(-6) for all analyses). Pooled analysis demonstrated AAO of 53.1 (±11.2) and 58.1 (±10.6) years for severe and mild GBA mutation carriers, respectively (p = 4.3 × 10(-5)). These data demonstrate that mild and severe heterozygous GBA mutations differentially affect the risk and the AAO of PD. Our results have important implications for genetic counseling and clinical follow-up. © 2015 American Academy of Neurology.

The Memory Cytotoxic T-Lymphocyte (CTL) Response to Human Cytomegalovirus Infection Contains Individual Peptide-Specific CTL Clones That Have Undergone Extensive Expansion In Vivo

PubMed Central

Weekes, Michael P.; Wills, Mark R.; Mynard, Kim; Carmichael, Andrew J.; Sissons, J. G. Patrick

1999-01-01

Human cytomegalovirus (HCMV)-specific CD8+ cytotoxic T lymphocytes (CTL) appear to play an important role in the control of virus replication and in protection against HCMV-related disease. We have previously reported high frequencies of memory CTL precursors (CTLp) specific to the HCMV tegument protein pp65 in the peripheral blood of healthy virus carriers. In some individuals, the CTL response to this protein is focused on only a single epitope, whereas in other virus carriers CTL recognized multiple epitopes which we identified by using synthetic peptides. We have analyzed the clonal composition of the memory CTL response to four of these pp65 epitopes by sequencing the T-cell receptors (TCR) of multiple independently derived epitope-specific CTL clones, which were derived by formal single-cell cloning or from clonal CTL microcultures. In all cases, we have observed a high degree of clonal focusing: the majority of CTL clones specific to a defined pp65 peptide from any one virus carrier use only one or two different TCRs at the level of the nucleotide sequence. Among virus carriers who have the same major histocompatibility complex (MHC) class I allele, we observed that CTL from different donors that recognize the same peptide-MHC complex often used the same Vβ segment, although other TCR gene segments and CDR3 length were not in general conserved. We have also examined the clonal composition of CTL specific to pp65 peptides in asymptomatic human immunodeficiency virus-infected individuals. We have observed a similarly focused peptide-specific CTL response. Thus, the large population of circulating HCMV peptide-specific memory CTLp in virus carriers in fact contains individual CTL clones that have undergone extensive clonal expansion in vivo. PMID:9971792

A Precision, Low-Cost GPS-Based Synchronization Scheme for Improved AM Reception.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Stephen Fulton; Moore, Anthony

2009-01-01

This paper describes a highly accurate carrier-frequency synchronization scheme for actively, automatically locking multiple, remotely located AM broadcast transmitters to a common frequency/timing reference source such as GPS. The extremely tight frequency lock (to ~1 part in 109 or better) permits the effective elimination of audible and even sub-audible beats between the local (desired) station s carrier signal and the distant stations carriers, usually received via skywave propagation during the evening and nighttime hours. These carrier-beat components cause annoying modulations of the desired station s audio at the receiver and concurrent distortion of the audio modulation from the distant station(s)more » and often cause listeners to tune out due to the poor reception quality. Significant reduction or elimination of the beats and related effects will greatly enlarge the effective (interference-limited) listening area of the desired station (from 4 to 10 times as indicated in our tests) and simultaneously reduce the corresponding interference of the local transmitter to the distant stations as well. In addition, AM stereo (CQUAM) reception will be particularly improved by minimizing the phase shifts induced by co-channel interfering signals; HD will also benefit via reduction in beats from analog signals. The automatic frequency-control hardware described is inexpensive ($1-2K), requires no periodic recalibration, has essentially zero long-term drift, and could employ alternate wide-area frequency references of suitable accuracy, including broadcasts from WWVB, LORAN-C, and equivalent sources. The basic configuration of the GPS-disciplined oscillator which solves this problem is extremely simple. The main oscillator is a conventional high-stability quartz-crystal type. To counter long-term drifts, the oscillator is slightly adjusted to track a high-precision source of standard frequency obtained from a specialized GPS receiver (or other source), usually at 10.000 MHz. This very stable local reference frequency is then used as a clock for a standard digitally implemented frequency synthesizer, which is programmed to generate the specific (AM broadcast) transmitter carrier frequency desired. The stability of the disciplining source, typically ~ 1 part in 109 to 1011, is thus transferred to the final AM transmitter carrier output frequency. Generally, an AM radio listener during the evening and nighttime hours, and to a lesser extent in the early morning, receives undesired skywave signals from several distant stations as well as the desired local (groundwave) signal. If all of these signals are within about 0.01-0.001 Hz of each other, any resulting carrier beats will be of such long periods that the beats will be effectively suppressed by the action of the receiver s AGC circuitry and thus be unnoticeable to the listener. Many modern, synthesizer-based transmitters can directly lock to the precision disciplined 10-MHz source, while older units usually require references at either1 e, 2 e, or 4 e the final frequency. In these latter cases, the existing transmitter crystal can usually be satisfactorily pulled via injection locking. The effectiveness of the synchronization concept to reduce interference effects was demonstrated in a laboratory test setup. Many hours of careful subjective listening were conducted, with the two interfering units both precisely on-frequency with the main unit (synchronous operation) and with the two interferers at various frequency offsets, from below 1 Hz to above 10 Hz.« less

A code-aided carrier synchronization algorithm based on improved nonbinary low-density parity-check codes

NASA Astrophysics Data System (ADS)

Bai, Cheng-lin; Cheng, Zhi-hui

2016-09-01

In order to further improve the carrier synchronization estimation range and accuracy at low signal-to-noise ratio ( SNR), this paper proposes a code-aided carrier synchronization algorithm based on improved nonbinary low-density parity-check (NB-LDPC) codes to study the polarization-division-multiplexing coherent optical orthogonal frequency division multiplexing (PDM-CO-OFDM) system performance in the cases of quadrature phase shift keying (QPSK) and 16 quadrature amplitude modulation (16-QAM) modes. The simulation results indicate that this algorithm can enlarge frequency and phase offset estimation ranges and enhance accuracy of the system greatly, and the bit error rate ( BER) performance of the system is improved effectively compared with that of the system employing traditional NB-LDPC code-aided carrier synchronization algorithm.

Prevalence and mutations of β-thalassemia trait and abnormal hemoglobins in premarital screening in Çanakkale province, Turkey

PubMed Central

Uludağ, A; Uludağ, A; Ertekin, YH; Tekin, M; Kütük, B; Silan, F; Özdemir, Ö

2016-01-01

Abstract The prevalence of β-thalassemia (β-thal) carriers in Turkey varies according to region but in general it is 2.0%. Çanakkale is a city in the Aegean region of Turkey but no study about β-thal frequency in Çanakkale has been published to date. In this study, we aimed to investigate the frequency of β-thal mutations in this province. A total of 4452 couples (8904 individuals) applied for premarital thalassemia scans at the Çanakkale State Health Directorate Laboratory between January 2008 and June 2012 and scanning was done with high performance liquid chromatography (HPLC). Of 125 β-thal carriers seen at the Medical Genetics Clinic, Çanakkale Onsekiz Mart University, Çanakkale, Turkey, for genetic counseling, 46 participated in the study. The remaining 79 patients could not be reached. The prevalence for β-thal carriers in Çanakkale was identified as 1.4% (125/8904). One couple were both β-thal carriers. β-Globin gene analysis of 46 carriers found the total frequency of the three most common mutations was 45.6%. These mutations were found to be HBB: c.93-21G>A [IVS-I-110 (G>A)], 26.08% (12/46); HBB: c.17_ 18delCT [codon 5 (‒CT)], 10.85% (5/46); HBB: c.20delA [codon 6 (‒A)] 8.69% (4/46). This is the first report on the frequency and mutation profiles of β-thal for Çanakkale. The incidence of β-thal carriers in Çanakkale is below the average for Turkey. The most frequently observed mutation profile and rate of β-thal in our region is different from the other regions of Turkey. PMID:27785405

The frequency spectrum crisis - Issues and answers

NASA Astrophysics Data System (ADS)

Armes, G. L.

The frequency spectrum represents a unique resource which can be overtaxed. In the present investigation, it is attempted to evalute the demand for satellite and microwave services. Dimensions of increased demand are discussed, taking into account developments related to the introduction of the personal computer, the activities of the computer and communications industries in preparation for the office of the future, and electronic publishing. Attention is given to common carrier spectrum congestion, common carrier microwave, satellite communications, teleports, international implications, satellite frequency bands, satellite spectrum implications, alternatives regarding the utilization of microwave frequency bands, U.S. Government spectrum utilization, and the impact at C-band.

[The parallelisms in of sound signal of domestic sheep and Northern fur seals].

PubMed

Nikol'skiĭ, A A; Lisitsina, T Iu

2011-01-01

The parallelisms in communicative behavior of domestic sheep and Northern fur seals within a herd are accompanied by parallelisms in parameters of sound signal, the calling scream. This signal ensures ties between babies and their mothers at a long distance. The basis of parallelisms is formed by amplitude modulation at two levels: the one being a direct amplitude modulation of the carrier frequency and the other--modulation of the carrier frequency oscillation. Parallelisms in the signal oscillatory process result in corresponding parallelisms in the structure of its frequency spectrum.

Wavelength Division Multiplexing Scheme for Radio-Frequency Single Electron Transistors

NASA Technical Reports Server (NTRS)

Stevenson, Thomas R.; Pellerano, F. A.; Stahle, C. M.; Aidala, K.; Schoelkopf, R. J.; Krebs, Carolyn (Technical Monitor)

2001-01-01

We describe work on a wavelength division multiplexing scheme for radio-frequency single electron transistors. We use a network of resonant impedance matching circuits to direct applied rf carrier waves to different transistors depending on carrier frequency. Using discrete components, we made a two-channel demonstration of this concept and successfully reconstructed input signals with small levels of cross coupling. A lithographic version of the rf circuits had measured parameters in agreement with electromagnetic modeling, with reduced cross capacitance and inductance, and should allow 20 to 50 channels to be multiplexed.

Collinear interferometer with variable delay for carrier-envelope offset frequency measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pawlowska, Monika; Ozimek, Filip; Fita, Piotr

2009-08-15

We demonstrate a novel scheme for measuring the carrier-envelope offset frequency in a femtosecond optical frequency comb. Our method is based on a common-path interferometer with a calcite Babinet-Soleil compensator employed to control the delay between the two interfering beams of pulses. The large delay range (up to 8 ps) of our device is sufficient for systems that rely on spectral broadening in microstructured fibers. We show an experimental proof that the stability of a common-path arrangement is superior to that of the standard interferometers.

Collinear interferometer with variable delay for carrier-envelope offset frequency measurement

NASA Astrophysics Data System (ADS)

Pawłowska, Monika; Ozimek, Filip; Fita, Piotr; Radzewicz, Czesław

2009-08-01

We demonstrate a novel scheme for measuring the carrier-envelope offset frequency in a femtosecond optical frequency comb. Our method is based on a common-path interferometer with a calcite Babinet-Soleil compensator employed to control the delay between the two interfering beams of pulses. The large delay range (up to 8 ps) of our device is sufficient for systems that rely on spectral broadening in microstructured fibers. We show an experimental proof that the stability of a common-path arrangement is superior to that of the standard interferometers.

47 CFR 32.11 - Classification of companies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Classification of companies. 32.11 Section 32... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES General Instructions § 32.11 Classification of... exchange carrier(s) as defined in section 251(h) of the Communications Act, and any other carriers that the...

47 CFR 51.907 - Transition of price cap carrier access charges.

Code of Federal Regulations, 2013 CFR

2013-10-01

... carrier shall, in accordance with bill-and-keep, as defined in § 51.713, revise and refile its interstate.... 51.907 Section 51.907 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Transitional Access Service Pricing § 51.907 Transition of price cap...

47 CFR 51.907 - Transition of price cap carrier access charges.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., each Price Cap carrier shall, in accordance with bill-and-keep, as defined in § 51.713, revise and.... 51.907 Section 51.907 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Transitional Access Service Pricing § 51.907 Transition of price cap...

47 CFR 51.907 - Transition of price cap carrier access charges.

Code of Federal Regulations, 2012 CFR

2012-10-01

... carrier shall, in accordance with bill-and-keep, as defined in § 51.713, revise and refile its interstate.... 51.907 Section 51.907 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Transitional Access Service Pricing § 51.907 Transition of price cap...

19 CFR 122.171 - Description of program.

Code of Federal Regulations, 2010 CFR

2010-04-01

... TREASURY AIR COMMERCE REGULATIONS Air Carrier Smuggling Prevention Program § 122.171 Description of program. The Air Carrier Smuggling Prevention Program (ACSPP) is designed to enlist the cooperation of the air carriers, as defined in 19 U.S.C. 1584 note, in Customs efforts to prevent the smuggling of controlled...

Exploiting elastic anharmonicity in aluminum nitride matrix for phase-synchronous frequency reference generation

NASA Astrophysics Data System (ADS)

Ghatge, Mayur; Tabrizian, Roozbeh

2018-03-01

A matrix of aluminum-nitride (AlN) waveguides is acoustically engineered to realize electrically isolated phase-synchronous frequency references through nonlinear wave-mixing. AlN rectangular waveguides are cross-coupled through a periodically perforated plate that is engineered to have a wide acoustic bandgap around a desirable frequency ( f1≈509 MHz). While the coupling plate isolates the matrix from resonant vibrations of individual waveguide constituents at f1, it is transparent to the third-order harmonic waves (3f1) that are generated through nonlinear wave-mixing. Therefore, large-signal excitation of the f1 mode in a constituent waveguide generates acoustic waves at 3f1 with an efficiency defined by elastic anharmonicity of the AlN film. The phase-synchronous propagation of the third harmonic through the matrix is amplified by a high quality-factor resonance mode at f2≈1529 MHz, which is sufficiently close to 3f1 (f2 ≅ 3f1). Such an architecture enables realization of frequency-multiplied and phase-synchronous, yet electrically and spectrally isolated, references for multi-band/carrier and spread-spectrum wireless communication systems.

Stabilization of a self-referenced, prism-based, Cr:forsterite laser frequency comb using an intracavity prism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tillman, Karl A.; Thapa, Rajesh; Knabe, Kevin

2009-12-20

The frequency comb from a prism-based Cr:forsterite laser has been frequency stabilized using intracavity prism insertion and pump power modulation. Absolute frequency measurements of a CW fiber laser stabilized to the P(13) transition of acetylene demonstrate a fractional instability of {approx}2x10{sup -11} at a 1 s gate time, limited by a commercial Global Positioning System (GPS)-disciplined rubidium oscillator. Additionally, absolute frequency measurements made simultaneously using a second frequency comb indicate relative instabilities of 3x10{sup -12} for both combs for a 1 s gate time. Estimations of the carrier-envelope offset frequency linewidth based on relative intensity noise and the response dynamicsmore » of the carrier-envelope offset to pump power changes confirm the observed linewidths.« less

Pilot-Assisted Channel Estimation for Orthogonal Multi-Carrier DS-CDMA with Frequency-Domain Equalization

NASA Astrophysics Data System (ADS)

Shima, Tomoyuki; Tomeba, Hiromichi; Adachi, Fumiyuki

Orthogonal multi-carrier direct sequence code division multiple access (orthogonal MC DS-CDMA) is a combination of time-domain spreading and orthogonal frequency division multiplexing (OFDM). In orthogonal MC DS-CDMA, the frequency diversity gain can be obtained by applying frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion to a block of OFDM symbols and can improve the bit error rate (BER) performance in a severe frequency-selective fading channel. FDE requires an accurate estimate of the channel gain. The channel gain can be estimated by removing the pilot modulation in the frequency domain. In this paper, we propose a pilot-assisted channel estimation suitable for orthogonal MC DS-CDMA with FDE and evaluate, by computer simulation, the BER performance in a frequency-selective Rayleigh fading channel.

A Hybrid Solution for Simultaneous Transfer of Ultrastable Optical Frequency, RF Frequency, and UTC Time-Tags Over Optical Fiber.

PubMed

Krehlik, Przemyslaw; Schnatz, Harald; Sliwczynski, Lukasz

2017-12-01

We describe a fiber-optic solution for simultaneous distribution of all signals generated at today's most advanced time and frequency laboratories, i.e., an ultrastable optical reference frequency derived from an optical atomic clock, a radio frequency precisely linked to a realization of the SI-Second, and a realization of an atomic timescale, being the local representation of the virtual, global UTC timescale. In our solution both the phase of the optical carrier and the delay of electrical signals (10-MHz frequency reference and one-pulse-per-second time tags) are stabilized against environmental perturbations influencing the fiber link instability and accuracy. We experimentally demonstrate optical transfer stabilities of and for 100 s averaging period, for optical carrier and 10-MHz signals, respectively.

Using individual differences to test the role of temporal and place cues in coding frequency modulation

PubMed Central

Whiteford, Kelly L.; Oxenham, Andrew J.

2015-01-01

The question of how frequency is coded in the peripheral auditory system remains unresolved. Previous research has suggested that slow rates of frequency modulation (FM) of a low carrier frequency may be coded via phase-locked temporal information in the auditory nerve, whereas FM at higher rates and/or high carrier frequencies may be coded via a rate-place (tonotopic) code. This hypothesis was tested in a cohort of 100 young normal-hearing listeners by comparing individual sensitivity to slow-rate (1-Hz) and fast-rate (20-Hz) FM at a carrier frequency of 500 Hz with independent measures of phase-locking (using dynamic interaural time difference, ITD, discrimination), level coding (using amplitude modulation, AM, detection), and frequency selectivity (using forward-masking patterns). All FM and AM thresholds were highly correlated with each other. However, no evidence was obtained for stronger correlations between measures thought to reflect phase-locking (e.g., slow-rate FM and ITD sensitivity), or between measures thought to reflect tonotopic coding (fast-rate FM and forward-masking patterns). The results suggest that either psychoacoustic performance in young normal-hearing listeners is not limited by peripheral coding, or that similar peripheral mechanisms limit both high- and low-rate FM coding. PMID:26627783

Using individual differences to test the role of temporal and place cues in coding frequency modulation.

PubMed

Whiteford, Kelly L; Oxenham, Andrew J

2015-11-01

The question of how frequency is coded in the peripheral auditory system remains unresolved. Previous research has suggested that slow rates of frequency modulation (FM) of a low carrier frequency may be coded via phase-locked temporal information in the auditory nerve, whereas FM at higher rates and/or high carrier frequencies may be coded via a rate-place (tonotopic) code. This hypothesis was tested in a cohort of 100 young normal-hearing listeners by comparing individual sensitivity to slow-rate (1-Hz) and fast-rate (20-Hz) FM at a carrier frequency of 500 Hz with independent measures of phase-locking (using dynamic interaural time difference, ITD, discrimination), level coding (using amplitude modulation, AM, detection), and frequency selectivity (using forward-masking patterns). All FM and AM thresholds were highly correlated with each other. However, no evidence was obtained for stronger correlations between measures thought to reflect phase-locking (e.g., slow-rate FM and ITD sensitivity), or between measures thought to reflect tonotopic coding (fast-rate FM and forward-masking patterns). The results suggest that either psychoacoustic performance in young normal-hearing listeners is not limited by peripheral coding, or that similar peripheral mechanisms limit both high- and low-rate FM coding.

A Computer Model of a Phase Lock Loop

NASA Technical Reports Server (NTRS)

Shelton, Ralph Paul

1973-01-01

A computer model is reported of a PLL (phase-lock loop), preceded by a bandpass filter, which is valid when the bandwidth of the bandpass filter is of the same order of magnitude as the natural frequency of the PLL. New results for the PLL natural frequency equal to the bandpass filter bandwidth are presented for a second order PLL operating with carrier plus noise as the input. However, it is shown that extensions to higher order loops, and to the case of a modulated carrier are straightforward. The new results presented give the cycle skipping rate of the PLL as a function of the input carrier to noise ratio when the PLL natural frequency is equal to the bandpass filter bandwidth. Preliminary results showing the variation of the output noise power and cycle skipping rates of the PLL as a function of the loop damping ratio for the PLL natural frequency equal to the bandpass filter bandwidth are also included.

Robust frequency stabilization of multiple spectroscopy lasers with large and tunable offset frequencies.

PubMed

Nevsky, A; Alighanbari, S; Chen, Q-F; Ernsting, I; Vasilyev, S; Schiller, S; Barwood, G; Gill, P; Poli, N; Tino, G M

2013-11-15

We have demonstrated a compact, robust device for simultaneous absolute frequency stabilization of three diode lasers whose carrier frequencies can be chosen freely relative to the reference. A rigid ULE multicavity block is employed, and, for each laser, the sideband locking technique is applied. A small lock error, computer control of frequency offset, wide range of frequency offset, simple construction, and robust operation are the useful features of the system. One concrete application is as a stabilization unit for the cooling and trapping lasers of a neutral-atom lattice clock. The device significantly supports and improves the clock's operation. The laser with the most stringent requirements imposed by this application is stabilized to a line width of 70 Hz, and a residual frequency drift less than 0.5 Hz/s. The carrier optical frequency can be tuned over 350 MHz while in lock.

Nystagmus as an early ocular alteration in Machado-Joseph disease (MJD/SCA3)

PubMed Central

2014-01-01

Background Machado-Joseph disease (MJD), also named spinocerebellar ataxia type 3 (SCA3) is the most common autosomal dominant ataxia worldwide. Although nystagmus is one of the most frequently reported ocular alterations in MJD patients its behaviour during the course of the disease, namely in its early stages, has only recently started to be investigated. The main goal of this work was to characterize the frequency of nystagmus in symptomatic and presymptomatic carriers of the MJD mutation, and investigate its usefulness as an early indicator of the disease. Methods We conducted an observational study of Azorean MJD family members, comprising a total of 158 subjects which underwent neurological evaluation. Sixty eight were clinically and molecularly diagnosed with MJD, 48 were confirmed asymptomatic carriers and 42 were confirmed non-carriers of the MJD mutation. The frequency of nystagmus was calculated for the 3 groups. Results Nystagmus was present in 88% of the MJD patients. Seventeen percent of the at-risk subjects with a carrier result in the molecular test and none of the 42 individuals who received a non-carrier test result displayed nystagmus (p < 0.006). Although not reaching statistical significance, symptomatic subjects showing nystagmus had a tendency for a higher length of the CAG tract in the expanded allele, when compared to individuals who did not have nystagmus. Conclusions The frequency of nystagmus in asymptomatic carriers and its absence in non-carriers of the mutation, suggests that nystagmus may appear before gait disturbance and can thus be considered an early sign of MJD. PMID:24450306

Tay-Sachs disease preconception screening in Australia: self-knowledge of being an Ashkenazi Jew predicts carrier state better than does ancestral origin, although there is an increased risk for c.1421 + 1G > C mutation in individuals with South African heritage.

PubMed

Lew, Raelia; Burnett, Leslie; Proos, Anné

2011-12-01

The Australasian Community Genetics Program provided a preconception screening for Tay-Sachs disease (TSD) to 4,105 Jewish high school students in Sydney and Melbourne over the 12-year period 1995-2007. By correlating the frequencies of mutant HEXA, MIM *606869 (gene map locus 15q23-q24) alleles with subjects' nominated ethnicity (Ashkenazi/Sephardi/Mixed) and grandparental birthplaces, we established that Ashkenazi ethnicity is a better predictor of TSD carrier status than grandparental ancestral origins. Screening self-identified Ashkenazi subjects detected 95% of TSD carriers (carrier frequency 1:25). Having mixed Ashkenazi and non-Ashkenazi heritage reduced the carrier frequency (1:97). South African heritage conveyed a fourfold risk of c.1421 + 1G > C mutation compared with other AJ subjects (odds ratio (OR), 4.19; 95% confidence interval (CI), 1.83-9.62, p = 0.001), but this was the only specific case of ancestral origin improving diagnostic sensitivity over that based on determining Ashkenazi ethnicity. Carriers of c.1278insTATC mutations were more likely to have heritage from Western Europe (OR, 1.65 (95% CI, 1.04-2.60), p = 0.032) and South Eastern Europe (OR, 1.77 (95% CI, 1.14-2.73), p = 0.010). However, heritage from specific European countries investigated did not significantly alter the overall odds of TSD carrier status.

Increased Pilus Production Conferred by a Naturally Occurring Mutation Alters Host-Pathogen Interaction in Favor of Carriage in Streptococcus pyogenes

PubMed Central

Olsen, Randall J.; Cantu, Concepcion; Pallister, Kyler B.; Guerra, Fermin E.; Voyich, Jovanka M.; Musser, James M.

2017-01-01

ABSTRACT Studies of the human pathogen group A Streptococcus (GAS) define the carrier phenotype to be an increased ability to adhere to and persist on epithelial surfaces and a decreased ability to cause disease. We tested the hypothesis that a single amino acid change (Arg135Gly) in a highly conserved sensor kinase (LiaS) of a poorly defined GAS regulatory system contributes to a carrier phenotype through increased pilus production. When introduced into an emm serotype-matched invasive strain, the carrier allele (the gene encoding the LiaS protein with an arginine-to-glycine change at position 135 [liaSR135G]) recapitulated a carrier phenotype defined by an increased ability to adhere to mucosal surfaces and a decreased ability to cause disease. Gene transcript analyses revealed that the liaS mutation significantly altered transcription of the genes encoding pilus in the presence of bacitracin. Elimination of pilus production in the isogenic carrier mutant decreased its ability to colonize the mouse nasopharynx and to adhere to and be internalized by cultured human epithelial cells and restored the virulence phenotype in a mouse model of necrotizing fasciitis. We also observed significantly reduced survival of the isogenic carrier mutant compared to that of the parental invasive strain after exposure to human neutrophils. Elimination of pilus in the isogenic carrier mutant increased the level of survival after exposure to human neutrophils to that for the parental invasive strain. Together, our data demonstrate that the carrier mutation (liaSR135G) affects pilus expression. Our data suggest new mechanisms of pilus gene regulation in GAS and that the invasiveness associated with pilus gene regulation in GAS differs from the enhanced invasiveness associated with increased pilus production in other bacterial pathogens. PMID:28264907

Spread-Spectrum Carrier Estimation With Unknown Doppler Shift

NASA Technical Reports Server (NTRS)

DeLeon, Phillip L.; Scaife, Bradley J.

1998-01-01

We present a method for the frequency estimation of a BPSK modulated, spread-spectrum carrier with unknown Doppler shift. The approach relies on a classic periodogram in conjunction with a spectral matched filter. Simulation results indicate accurate carrier estimation with processing gains near 40. A DSP-based prototype has been implemented for real-time carrier estimation for use in New Mexico State University's proposal for NASA's Demand Assignment Multiple Access service.

47 CFR 15.113 - Power line carrier systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-interference basis in accordance with § 15.5 of this part. If harmful interference occurs, the electric power... frequencies. (e) Power line carrier system apparatus shall conform to such engineering standards as may be... 47 Telecommunication 1 2012-10-01 2012-10-01 false Power line carrier systems. 15.113 Section 15...

77 FR 59244 - Agency Information Collection Activities; Extension of Currently-Approved Information Collection...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-26

...: Class I Motor Carriers of Passengers. Estimated Number of Respondents: 2 (per year). Estimated Time per Response: 18 minutes per response. Expiration Date: September 30, 2012. Frequency of Response: Annually and..., passenger carriers are classified into two groups: (1) Class I carriers are those having average annual...

An OKQPSK modem incorporating numerically controlled carrier synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oetken, R.E.

1988-04-04

The feasibility of incorporating numerically controlled oscillators (NCO) in communication related applications is evaluated. NCO generation of sinusoids may prove useful in systems requiring precise frequency control, tuning linearity, and orthogonality versus frequency. An OKQPSK modem operating at a data rate of 200 kb/s was fabricated. The modem operates in a back to back hardwired channel and thus does not incorporate carrier or symbol timing recovery. Spectra of the NCO generated sinusoids are presented along with waveforms from the modulation and demodulation process. Generation of sinusoids in the digital domain is a viable alternative to analog oscillators. Implementation of anmore » NCO should be considered when frequency allocation, tuning bandwidth, or frequency hopped transmission requires precise frequency synthesis. 24 figs.« less

Extended-area nanostructuring of TiO2 with femtosecond laser pulses at 400 nm using a line focus.

PubMed

Das, Susanta Kumar; Dasari, Kiran; Rosenfeld, Arkadi; Grunwald, Ruediger

2010-04-16

An efficient way to generate nanoscale laser-induced periodic surface structures (LIPSS) in rutile-type TiO(2) with frequency-converted femtosecond laser pulses at wavelengths around 400 nm is reported. Extended-area structuring on fixed and moving substrates was obtained by exploiting the line focus of a cylindrical lens. Under defined conditions with respect to pulse number, pulse energy and scanning velocity, two types of ripple-like LIPSS with high and low spatial frequencies (HSFL, LSFL) with periods in the range of 90 nm and 340 nm, respectively, were formed. In particular, lower numbers of high energetic pulses favour the generation of LSFL whereas higher numbers of lower energetic pulses enable the preferential creation of HSFL. Theoretical calculations on the basis of the Drude model support the assumption that refractive index changes by photo-excited carriers are a major mechanism responsible for LSFL. Furthermore, the appearance of random substructures as small as 30 nm superimposing low spatial frequency ripples is demonstrated and their possible origin is discussed.

Signal processing for the profoundly deaf.

PubMed

Boothyroyd, A

1990-01-01

Profound deafness, defined here as a hearing loss in excess of 90 dB, is characterized by high thresholds, reduced hearing range in the intensity and frequency domains, and poor resolution in the frequency and time domains. The high thresholds call for hearing aids with unusually high gains or remote microphones that can be placed close to the signal source. The former option creates acoustic feedback problems for which digital signal processing may yet offer solutions. The latter option calls for carrier wave technology that is already available. The reduced frequency and intensity ranges would appear to call for frequency and/or amplitude compression. It might also be argued, however, that any attempts to compress the acoustic signal into the limited hearing range of the profoundly deaf will be counterproductive because of poor frequency and time resolution, especially when the signal is present in noise. In experiments with a 2-channel compression system, only 1 of 9 subjects showed an improvement of perception with the introduction of fast-release (20 ms) compression. The other 8 experienced no benefit or a slight deterioration of performance. These results support the concept of providing the profoundly deaf with simpler, rather than more complex, patterns, perhaps through the use of feature extraction hearing aids. Data from users of cochlear implants already employing feature extraction techniques also support this concept.

Speaking-rate-induced variability in F2 trajectories.

PubMed

Tjaden, K; Weismer, G

1998-10-01

This study examined speaking-rate-induced spectral and temporal variability of F2 formant trajectories for target words produced in a carrier phrase at speaking rates ranging from fast to slow. F2 onset frequency measured at the first glottal pulse following the stop consonant release in target words was used to quantify the extent to which adjacent consonantal and vocalic gestures overlapped; F2 target frequency was operationally defined as the first occurrence of a frequency minimum or maximum following F2 onset frequency. Regression analyses indicated 70% of functions relating F2 onset and vowel duration were statistically significant. The strength of the effect was variable, however, and the direction of significant functions often differed from that predicted by a simple model of overlapping, sliding gestures. Results of a partial correlation analysis examining interrelationships among F2 onset, F2 target frequency, and vowel duration across the speaking rate range indicated that covariation of F2 target with vowel duration may obscure the relationship between F2 onset and vowel duration across rate. The results further suggested that a sliding based model of acoustic variability associated with speaking rate change only partially accounts for the present data, and that such a view accounts for some speakers' data better than others.

High-power S-band experiment study: Objectives, description, planning and operation of experiment for ATS-G spacecraft

NASA Technical Reports Server (NTRS)

Walp, R. M.

1972-01-01

The results of a study to develop and define requirements for the high power S-band experiment for the ATS-G are summarized. The objectives of the experiment are: (1) to demonstrate high power technology at S-band frequencies in orbiting spacecraft, (2) to employ high power carrier from the spacecraft for conducting interference measurements with Instructional Television Fixed Service systems, and (3) to provide means for performing educationally oriented applications experiments. Experiment organization and operation, and hardware for flight on the ATS-G spacecraft are described. Earth stations designed for the experiment as well as other special ground equipment are also described.

A Simplified Baseband Prefilter Model with Adaptive Kalman Filter for Ultra-Tight COMPASS/INS Integration

PubMed Central

Luo, Yong; Wu, Wenqi; Babu, Ravindra; Tang, Kanghua; Luo, Bing

2012-01-01

COMPASS is an indigenously developed Chinese global navigation satellite system and will share many features in common with GPS (Global Positioning System). Since the ultra-tight GPS/INS (Inertial Navigation System) integration shows its advantage over independent GPS receivers in many scenarios, the federated ultra-tight COMPASS/INS integration has been investigated in this paper, particularly, by proposing a simplified prefilter model. Compared with a traditional prefilter model, the state space of this simplified system contains only carrier phase, carrier frequency and carrier frequency rate tracking errors. A two-quadrant arctangent discriminator output is used as a measurement. Since the code tracking error related parameters were excluded from the state space of traditional prefilter models, the code/carrier divergence would destroy the carrier tracking process, and therefore an adaptive Kalman filter algorithm tuning process noise covariance matrix based on state correction sequence was incorporated to compensate for the divergence. The federated ultra-tight COMPASS/INS integration was implemented with a hardware COMPASS intermediate frequency (IF), and INS's accelerometers and gyroscopes signal sampling system. Field and simulation test results showed almost similar tracking and navigation performances for both the traditional prefilter model and the proposed system; however, the latter largely decreased the computational load. PMID:23012564

47 CFR 27.54 - Frequency stability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Frequency stability. 27.54 Section 27.54 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Technical Standards § 27.54 Frequency stability. The frequency stability shall be...

47 CFR 27.54 - Frequency stability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 2 2011-10-01 2011-10-01 false Frequency stability. 27.54 Section 27.54 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Technical Standards § 27.54 Frequency stability. The frequency stability shall be...

Interplay between plasmon and single-particle excitations in a metal nanocluster

DOE PAGES

Ma, Jie; Wang, Zhi; Wang, Lin-Wang

2015-12-17

Plasmon-generated hot carriers are used in photovoltaic or photochemical applications. However, the interplays between the plasmon and single-particle excitations in nanosystems have not been theoretically addressed using ab initio methods. Here we show such interplays in a Ag 55 nanocluster using real-time time-dependent density functional theory simulations. We find that the disappearance of the zero-frequency peak in the Fourier transform of the band-to-band transition coefficient is a hallmark of the plasmon. We show the importance of the d-states for hot-carrier generations. If the single-particle d-to-s excitations are resonant to the plasmon frequency, the majority of the plasmon energy will bemore » converted into hot carriers, and the overall hot-carrier generation is enhanced by the plasmon; if such resonance does not exist, we observe an intriguing Rabi oscillation between the plasmon and hot carriers. Phonons play a minor role in plasmonic dynamics in such small systems. Ultimately, this study provides guidance on improving plasmonic applications.« less

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

DOE PAGES

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.; ...

2017-11-10

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Interplay between plasmon and single-particle excitations in a metal nanocluster

PubMed Central

Ma, Jie; Wang, Zhi; Wang, Lin-Wang

2015-01-01

Plasmon-generated hot carriers are used in photovoltaic or photochemical applications. However, the interplays between the plasmon and single-particle excitations in nanosystems have not been theoretically addressed using ab initio methods. Here we show such interplays in a Ag55 nanocluster using real-time time-dependent density functional theory simulations. We find that the disappearance of the zero-frequency peak in the Fourier transform of the band-to-band transition coefficient is a hallmark of the plasmon. We show the importance of the d-states for hot-carrier generations. If the single-particle d-to-s excitations are resonant to the plasmon frequency, the majority of the plasmon energy will be converted into hot carriers, and the overall hot-carrier generation is enhanced by the plasmon; if such resonance does not exist, we observe an intriguing Rabi oscillation between the plasmon and hot carriers. Phonons play a minor role in plasmonic dynamics in such small systems. This study provides guidance on improving plasmonic applications. PMID:26673449

Effect of soil temperature on optical frequency transfer through unidirectional dense-wavelength-division-multiplexing fiber-optic links.

PubMed

Pinkert, T J; Böll, O; Willmann, L; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

2015-02-01

Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fiber network are presented. The relation between soil temperature changes on a buried optical fiber and frequency changes of an optical carrier through the fiber is modeled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2×298  km fiber link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that optical frequency dissemination is sufficiently stable to distribute and compare, e.g., rubidium frequency standards over standard DWDM optical fiber networks using unidirectional fibers.

47 CFR Appendix 1 to Subpart E of... - Glossary of Terms

Code of Federal Regulations, 2012 CFR

2012-10-01

... Part 95 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... frequencies. Reference frequencies from which the carrier frequency, suppressed or otherwise, may not deviate by more than the specified frequency tolerance. Crystal. Quartz piezo-electric element. Crystal...

Modeling and characterization of multipath in global navigation satellite system ranging signals

NASA Astrophysics Data System (ADS)

Weiss, Jan Peter

The Global Positioning System (GPS) provides position, velocity, and time information to users in anywhere near the earth in real-time and regardless of weather conditions. Since the system became operational, improvements in many areas have reduced systematic errors affecting GPS measurements such that multipath, defined as any signal taking a path other than the direct, has become a significant, if not dominant, error source for many applications. This dissertation utilizes several approaches to characterize and model multipath errors in GPS measurements. Multipath errors in GPS ranging signals are characterized for several receiver systems and environments. Experimental P(Y) code multipath data are analyzed for ground stations with multipath levels ranging from minimal to severe, a C-12 turboprop, an F-18 jet, and an aircraft carrier. Comparisons between receivers utilizing single patch antennas and multi-element arrays are also made. In general, the results show significant reductions in multipath with antenna array processing, although large errors can occur even with this kind of equipment. Analysis of airborne platform multipath shows that the errors tend to be small in magnitude because the size of the aircraft limits the geometric delay of multipath signals, and high in frequency because aircraft dynamics cause rapid variations in geometric delay. A comprehensive multipath model is developed and validated. The model integrates 3D structure models, satellite ephemerides, electromagnetic ray-tracing algorithms, and detailed antenna and receiver models to predict multipath errors. Validation is performed by comparing experimental and simulated multipath via overall error statistics, per satellite time histories, and frequency content analysis. The validation environments include two urban buildings, an F-18, an aircraft carrier, and a rural area where terrain multipath dominates. The validated models are used to identify multipath sources, characterize signal properties, evaluate additional antenna and receiver tracking configurations, and estimate the reflection coefficients of multipath-producing surfaces. Dynamic models for an F-18 landing on an aircraft carrier correlate aircraft dynamics to multipath frequency content; the model also characterizes the separate contributions of multipath due to the aircraft, ship, and ocean to the overall error statistics. Finally, reflection coefficients for multipath produced by terrain are estimated via a least-squares algorithm.

CFTR mutation distribution among U.S. Hispanic and African American individuals: evaluation in cystic fibrosis patient and carrier screening populations.

PubMed

Sugarman, Elaine A; Rohlfs, Elizabeth M; Silverman, Lawrence M; Allitto, Bernice A

2004-01-01

We reviewed CFTR mutation distribution among Hispanic and African American individuals referred for CF carrier screening and compared mutation frequencies to those derived from CF patient samples. Results from CFTR mutation analyses received from January 2001 through September 2003, were analyzed for four populations: Hispanic individuals with a CF diagnosis (n = 159) or carrier screening indication (n = 15,333) and African American individuals with a CF diagnosis (n = 108) or carrier screening indication (n = 8,973). All samples were tested for the same 87 mutation panel. In the Hispanic population, 42 mutations were identified: 30 in the patient population (77.5% detection rate) and 33 among carrier screening referrals. Five mutations not included in the ACMG/ACOG carrier screening panel (3876delA, W1089X, R1066C, S549N, 1949del84) accounted for 7.55% detection in patients and 5.58% among carriers. Among African American referrals, 33 different mutations were identified: 21 in the patient population (74.4% detection) and 23 in the carrier screening population. Together, A559T and 711+5G>A were observed at a detection rate of 3.71% in CF patients and 6.38% in carriers. The mutation distribution seen in both the carrier screening populations reflected an increased frequency of mutations with variable expression such as D1152H, R117H, and L206W. A detailed analysis of CFTR mutation distribution in the Hispanic and African American patient and carrier screening populations demonstrates that a diverse group of mutations is most appropriate for diagnostic and carrier screening in these populations. To best serve the increasingly diverse U.S. population, ethnic-specific mutations should be included in mutation panels.

47 CFR 15.247 - Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz.

Code of Federal Regulations, 2011 CFR

2011-10-01

... channel carrier frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of the hopping channel... have hopping channel carrier frequencies that are separated by 25 kHz or two-thirds of the 20 dB...: if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the system shall use at least 50...

47 CFR 15.247 - Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz.

Code of Federal Regulations, 2014 CFR

2014-10-01

... channel carrier frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of the hopping channel... have hopping channel carrier frequencies that are separated by 25 kHz or two-thirds of the 20 dB...: if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the system shall use at least 50...

47 CFR 15.247 - Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... channel carrier frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of the hopping channel... have hopping channel carrier frequencies that are separated by 25 kHz or two-thirds of the 20 dB...: if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the system shall use at least 50...

47 CFR 15.247 - Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz.

Code of Federal Regulations, 2013 CFR

2013-10-01

... channel carrier frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of the hopping channel... have hopping channel carrier frequencies that are separated by 25 kHz or two-thirds of the 20 dB...: if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the system shall use at least 50...

47 CFR 15.247 - Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz.

Code of Federal Regulations, 2012 CFR

2012-10-01

... channel carrier frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of the hopping channel... have hopping channel carrier frequencies that are separated by 25 kHz or two-thirds of the 20 dB...: if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the system shall use at least 50...

14 CFR 216.3 - Prohibition.

Code of Federal Regulations, 2010 CFR

2010-01-01

... REGULATIONS COMMINGLING OF BLIND SECTOR TRAFFIC BY FOREIGN AIR CARRIERS § 216.3 Prohibition. No foreign air carrier shall carry any blind sector traffic, as defined in this part, on any flight operating in air...

Power allocation and range performance considerations for a dual-frequency EBPSK/MPPSK system

NASA Astrophysics Data System (ADS)

Yao, Yu; Wu, Lenan; Zhao, Junhui

2017-12-01

Extended binary phase shift keying/M-ary position phase shift keying (EBPSK/MPPSK)-MODEM provides radar and communication functions on a single hardware platform with a single waveform. However, its range estimation accuracy is worse than continuous-wave (CW) radar because of the imbalance of power in two carrier frequencies. In this article, the power allocation method for dual-frequency EBPSK/MPPSK modulated systems is presented. The power of two signal transmitters is adequately allocated to ensure that the power in two carrier frequencies is equal. The power allocation ratios for two types of modulation systems are obtained. Moreover, considerations regarding the range of operation of the dual-frequency system are analysed. In addition to theoretical considerations, computer simulations are provided to illustrate the performance.

47 CFR Appendix 1 to Subpart E of... - Glossary of Terms

Code of Federal Regulations, 2013 CFR

2013-10-01

... typically includes a frequency monitoring system that initiates a MedRadio communications session. MedRadio... Part 95 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... station authorized in the CB. Channel frequencies. Reference frequencies from which the carrier frequency...

47 CFR Appendix 1 to Subpart E of... - Glossary of Terms

Code of Federal Regulations, 2010 CFR

2010-10-01

... which also typically includes a frequency monitoring system that initiates a MedRadio communications... Part 95 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... station authorized in the CB. Channel frequencies. Reference frequencies from which the carrier frequency...

47 CFR Appendix 1 to Subpart E of... - Glossary of Terms

Code of Federal Regulations, 2011 CFR

2011-10-01

... which also typically includes a frequency monitoring system that initiates a MedRadio communications... Part 95 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... station authorized in the CB. Channel frequencies. Reference frequencies from which the carrier frequency...

47 CFR Appendix 1 to Subpart E of... - Glossary of Terms

Code of Federal Regulations, 2014 CFR

2014-10-01

... typically includes a frequency monitoring system that initiates a MedRadio communications session. MedRadio... Part 95 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... station authorized in the CB. Channel frequencies. Reference frequencies from which the carrier frequency...

47 CFR 74.761 - Frequency tolerance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Booster Stations § 74.761 Frequency tolerance. The licensee of a low power TV, TV translator, or TV booster station shall maintain the transmitter output frequencies as set forth below. The frequency... channel carrier frequency if the low power TV, TV translator, or TV booster station is authorized with a...

47 CFR 74.761 - Frequency tolerance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Booster Stations § 74.761 Frequency tolerance. The licensee of a low power TV, TV translator, or TV booster station shall maintain the transmitter output frequencies as set forth below. The frequency... channel carrier frequency if the low power TV, TV translator, or TV booster station is authorized with a...

47 CFR 74.761 - Frequency tolerance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Booster Stations § 74.761 Frequency tolerance. The licensee of a low power TV, TV translator, or TV booster station shall maintain the transmitter output frequencies as set forth below. The frequency... channel carrier frequency if the low power TV, TV translator, or TV booster station is authorized with a...

47 CFR 74.761 - Frequency tolerance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Booster Stations § 74.761 Frequency tolerance. The licensee of a low power TV, TV translator, or TV booster station shall maintain the transmitter output frequencies as set forth below. The frequency... channel carrier frequency if the low power TV, TV translator, or TV booster station is authorized with a...

A microfluidic timer for timed valving and pumping in centrifugal microfluidics.

PubMed

Schwemmer, F; Zehnle, S; Mark, D; von Stetten, F; Zengerle, R; Paust, N

2015-03-21

Accurate timing of microfluidic operations is essential for the automation of complex laboratory workflows, in particular for the supply of sample and reagents. Here we present a new unit operation for timed valving and pumping in centrifugal microfluidics. It is based on temporary storage of pneumatic energy and time delayed sudden release of said energy. The timer is loaded at a relatively higher spinning frequency. The countdown is started by reducing to a relatively lower release frequency, at which the timer is released after a pre-defined delay time. We demonstrate timing for 1) the sequential release of 4 liquids at times of 2.7 s ± 0.2 s, 14.0 s ± 0.5 s, 43.4 s ± 1.0 s and 133.8 s ± 2.3 s, 2) timed valving of typical assay reagents (contact angles 36-78°, viscosities 0.9-5.6 mPa s) and 3) on demand valving of liquids from 4 inlet chambers in any user defined sequence controlled by the spinning protocol. The microfluidic timer is compatible to all wetting properties and viscosities of common assay reagents and does neither require assistive equipment, nor coatings. It can be monolithically integrated into a microfluidic test carrier and is compatible to scalable fabrication technologies such as thermoforming or injection molding.

Different definitions of neurodegeneration produce similar amyloid/neurodegeneration biomarker group findings

PubMed Central

Wiste, Heather J.; Weigand, Stephen D.; Knopman, David S.; Mielke, Michelle M.; Vemuri, Prashanthi; Lowe, Val; Senjem, Matthew L.; Gunter, Jeffrey L.; Reyes, Denise; Machulda, Mary M.; Roberts, Rosebud; Petersen, Ronald C.

2015-01-01

We recently demonstrated that the frequencies of biomarker groups defined by the presence or absence of both amyloidosis (A+) and neurodegeneration (N+) changed dramatically by age in cognitively non-impaired subjects. Our present objectives were to assess the consequences of defining neurodegeneration in five different ways on the frequency of subjects classified as N+, on the demographic associations with N+, and on amyloidosis and neurodegeneration (A/N) biomarker group frequencies by age. This was a largely cross-sectional observational study of 1331 cognitively non-impaired subjects aged 50–89 drawn from a population-based study of cognitive ageing. We assessed demographic associations with N+, and A/N biomarker group frequencies by age where A+ was defined by amyloid PET and N+ was defined in five different ways: (i) abnormal adjusted hippocampal volume alone; (ii) abnormal Alzheimer’s disease signature cortical thickness alone; (iii) abnormal fluorodeoxyglucose positron emission tomography alone; (iv) abnormal adjusted hippocampal volume or abnormal fluorodeoxyglucose positron emission tomography; and (v) abnormal Alzheimer’s disease signature cortical thickness or abnormal fluorodeoxyglucose positron emission tomography. For each N+ definition, participants were assigned to one of four biomarker groups; A−N−, A+N−, A−N+, or A+N+. The three continuous individual neurodegeneration measures were moderately correlated (rs = 0.42 to 0.54) but when classified as normal or abnormal had only weak agreement (κ = 0.20 to 0.29). The adjusted hippocampal volume alone definition classified the fewest subjects as N+ while the Alzheimer’s disease signature cortical thickness or abnormal fluorodeoxyglucose positron emission tomography definition classified the most as N+. Across all N+ definitions, N+ subjects tended to be older, more often male and APOE4 carriers, and performed less well on functional status and learning and memory than N− subjects. For all definitions of neurodegeneration, (i) the frequency of A−N− was 100% at age 50 and declined monotonically thereafter; (ii) the frequency of A+N− increased from age 50 to a maximum in the mid-70s and declined thereafter; and3 (iii) the frequency of A−N+ (suspected non-Alzheimer’s pathophysiology) and of A+N+ increased monotonically beginning in the mid-50s and mid-60s, respectively. Overall, different neurodegeneration measures provide similar but not completely redundant information. Despite quantitative differences, the overall qualitative pattern of the A−N−, A+N−, A−N+, and A+N+ biomarker group frequency curves by age were similar across the five different definitions of neurodegeneration. We conclude that grouping subjects by amyloidosis and neurodegeneration status (normal/abnormal) is robust to different imaging definitions of neurodegeneration and thus is a useful way for investigators throughout the field to communicate in a common classification framework. PMID:26428666

Multiple differences in calling songs and other traits between solitary and gregarious Mormon crickets from allopatric mtDNA clades

PubMed Central

Bailey, Nathan W; Gwynne, Darryl T; Bailey, William V; Ritchie, Michael G

2007-01-01

Background In acoustic species, traits such as male calling song are likely to diverge quickly between allopatric populations due to sexual selection, and divergence in parameters such as carrier frequency, chirp structure, and other important song characters can influence sexual isolation. Here we make use of two forms of Mormon crickets to examine differences in a broad suite of traits that have the potential to influence speciation via sexual isolation. Mormon crickets in "gregarious" populations aggregate into dense migratory bands, and females are the sexually competitive sex (sex-role reversal). There is also a non-outbreak "solitary" form. These two forms are largely but not perfectly correlated with a significant mtDNA subdivision within the species that is thought to have arisen in allopatry. Combined information about multiple, independently evolving traits, such as morphology and structural and behavioural differences in calling song, provides greater resolution of the overall differences between these allopatric populations, and allows us to assess their stage of divergence. We test two predictions, first that the forms differ in song and second that gregarious males are more reluctant to sing than solitary males due to sex role reversal. We also tested for a difference in the relationship between the size of the forewing resonator, the mirror, and carrier frequency, as most models of sound production in crickets indicate that mirror size should predict carrier frequency. Results Multivariate analyses showed that solitary and gregarious individuals from different populations representing the two mtDNA clades had almost non-overlapping distributions based on multiple song and morphological measurements. Carrier frequency differed between the two, and gregarious males were more reluctant to sing overall. Mirror size predicted carrier frequency; however, the relationship between mirror size and surface area varied between solitary and gregarious forms, suggesting that factors above and beyond mirror size contribute to carrier frequency. Conclusion The two clades of Mormon crickets differ in a broad suite of independent traits that probably justify subspecies status (the two can successfully mate so may not be reproductively isolated). However, our results emphasize the importance of carefully distinguishing the ultimate causation of differences between traits used to delineate species or subspecies boundaries. PMID:17241474

Incidence of bovine leukocyte adhesion deficiency, complex vertebral malformation, and deficiency of uridine-5-monophosphate synthase carriers in Brazilian Girolando cattle.

PubMed

Paiva, D S; Fonseca, I; Pinto, I S B; Ianella, P; Campos, T A; Caetano, A R; Paiva, S R; Silva, M V G B; Martins, M F

2013-08-29

Among the various hereditary diseases that have been widely studied in dairy cattle, bovine leukocyte adhesion deficiency (BLAD), deficiency of uridine-5-monophosphate synthase (DUMPS), and complex vertebral malformation (CVM) are noteworthy because of their high impact on overall herd productivity as a consequence of increased calf mortality. The aim of this study was to verify the frequency of carriers of BLAD, CVM, and DUMPS mutant alleles in cows and bulls from the National Girolando Progeny Test carried out in Brazil by using polymerase chain reaction (PCR)-restriction fragment length polymorphism and allele-specific PCR assays. A total of 777 animals were genotyped for BLAD, 783 for CVM, and 122 for DUMPS. The frequencies of carriers for BLAD and CVM were 0.77 and 1.53%, respectively, whereas no carriers of DUMPS were observed.

Terahertz-infrared electrodynamics of single-wall carbon nanotube films

NASA Astrophysics Data System (ADS)

Zhukova, E. S.; Grebenko, A. K.; Bubis, A. V.; Prokhorov, A. S.; Belyanchikov, M. A.; Tsapenko, A. P.; Gilshteyn, E. P.; Kopylova, D. S.; Gladush, Yu G.; Anisimov, A. S.; Anzin, V. B.; Nasibulin, A. G.; Gorshunov, B. P.

2017-11-01

Broad-band (4-20 000 cm-1) spectra of real and imaginary conductance of a set of high-quality pristine and AuCl3-doped single-walled carbon nanotube (SWCNT) films with different transparency are systematically measured. It is shown that while the high-energy (≥1 eV) response is determined by well-known interband transitions, the lower-energy electrodynamic properties of the films are fully dominated by unbound charge carriers. Their main spectral effect is seen as the free-carrier Drude-type contribution. Partial localization of these carriers leads to a weak plasmon resonance around 100 cm-1. At the lowest frequencies, below 10 cm-1, a gap-like feature is detected whose origin is associated with the energy barrier experienced by the carriers at the intersections between SWCNTs. It is assumed that these three mechanisms are universal and determine the low-frequency terahertz-infrared electrodynamics of SWCNT wafer-scale films.

Rate equation modeling of the frequency noise and the intrinsic spectral linewidth in quantum cascade lasers.

PubMed

Wang, Xing-Guang; Grillot, Frédéric; Wang, Cheng

2018-02-05

This work theoretically investigates the frequency noise (FN) characteristics of quantum cascade lasers (QCLs) through a three-level rate equation model, which takes into account both the carrier noise and the spontaneous emission noise through the Langevin approach. It is found that the power spectral density of the FN exhibits a broad peak due to the carrier noise induced carrier variation in the upper laser level, which is enhanced by the stimulated emission process. The peak amplitude is strongly dependent on the gain stage number and the linewidth broadening factor. In addition, an analytical formula of the intrinsic spectral linewidth of QCLs is derived based on the FN analysis. It is demonstrated that the laser linewidth can be narrowed by reducing the gain coefficient and/or accelerating the carrier scattering rates of the upper and the lower laser levels.

Optical conductivity of three and two dimensional topological nodal-line semimetals

NASA Astrophysics Data System (ADS)

Barati, Shahin; Abedinpour, Saeed H.

2017-10-01

The peculiar shape of the Fermi surface of topological nodal-line semimetals at low carrier concentrations results in their unusual optical and transport properties. We analytically investigate the linear optical responses of three- and two-dimensional nodal-line semimetals using the Kubo formula. The optical conductivity of a three-dimensional nodal-line semimetal is anisotropic. Along the axial direction (i.e., the direction perpendicular to the nodal-ring plane), the Drude weight has a linear dependence on the chemical potential at both low and high carrier dopings. For the radial direction (i.e., the direction parallel to the nodal-ring plane), this dependence changes from linear into quadratic in the transition from low into high carrier concentration. The interband contribution into optical conductivity is also anisotropic. In particular, at large frequencies, it saturates to a constant value for the axial direction and linearly increases with frequency along the radial direction. In two-dimensional nodal-line semimetals, no interband optical transition could be induced and the only contribution to the optical conductivity arises from the intraband excitations. The corresponding Drude weight is independent of the carrier density at low carrier concentrations and linearly increases with chemical potential at high carrier doping.

Background-free millimeter-wave ultra-wideband signal generation based on a dual-parallel Mach-Zehnder modulator.

PubMed

Zhang, Fangzheng; Pan, Shilong

2013-11-04

A novel scheme for photonic generation of a millimeter-wave ultra-wideband (MMW-UWB) signal is proposed and experimentally demonstrated based on a dual-parallel Mach-Zehnder modulator (DPMZM). In the proposed scheme, a single-frequency radio frequency (RF) signal is applied to one sub-MZM of the DPMZM to achieve optical suppressed-carrier modulation, and an electrical control pulse train is applied to the other sub-MZM biased at the minimum transmission point, to get an on/off switchable optical carrier. By filtering out the optical carrier with one of the first-order sidebands, and properly setting the amplitude of the control pulse, an MMW-UWB pulse train without the residual local oscillation is generated after photo-detection. The generated MMW-UWB signal is background-free, because the low-frequency components in the electrical spectrum are effectively suppressed. In the experiment, an MMW-UWB pulse train centered at 25 GHz with a 10-dB bandwidth of 5.5 GHz is successfully generated. The low frequency components are suppressed by 22 dB.

Carrier Envelope Phase Effect of a Long Duration Pulse in the Low Frequency Region

NASA Astrophysics Data System (ADS)

Zhao, Xi; Yang, Yu-Jun; Liu, Xue-Shen; Wang, Bing-Bing

2014-04-01

Using the characteristic of small energy difference between two high Rydberg states, we theoretically investigate the carrier envelope phase (CEP) effect in a bound-bound transition of an atom in a low-frequency long laser pulse with tens of optical cycles. Particularly, we first prepare a Rydberg state of a hydrogen-like atom by a laser field with the resonant frequency between this state and the ground state. Then by using a low-frequency long laser pulse interacting with this Rydberg atom, we calculate the population of another Rydberg state nearby this Rydberg state at the end of the laser pulse and find that the population changes dramatically with the CEP of the low-frequency pulse. This CEP effect is attributed to the interference between the positive-frequency and negative-frequency components in one-photon transition. These results may provide a method to measure the CEP value of a long laser pulse with low frequency.

Offset frequency dynamics and phase noise properties of a self-referenced 10 GHz Ti:sapphire frequency comb.

PubMed

Heinecke, Dirk C; Bartels, Albrecht; Diddams, Scott A

2011-09-12

This paper shows the experimental details of the stabilization scheme that allows full control of the repetition rate and the carrier-envelope offset frequency of a 10 GHz frequency comb based on a femtosecond Ti:sapphire laser. Octave-spanning spectra are produced in nonlinear microstructured optical fiber, in spite of the reduced peak power associated with the 10 GHz repetition rate. Improved stability of the broadened spectrum is obtained by temperature-stabilization of the nonlinear optical fiber. The carrier-envelope offset frequency and the repetition rate are simultaneously frequency stabilized, and their short- and long-term stabilities are characterized. We also measure the transfer of amplitude noise of the pump source to phase noise on the offset frequency and verify an increased sensitivity of the offset frequency to pump power modulation compared to systems with lower repetition rate. Finally, we discuss merits of this 10 GHz system for the generation of low-phase-noise microwaves from the photodetected pulse train.

An adaptive narrow band frequency modulation voice communication system

NASA Technical Reports Server (NTRS)

Wishna, S.

1972-01-01

A narrow band frequency modulation communication system is described which provides for the reception of good quality voice at low carrier-to-noise ratios. The high level of performance is obtained by designing a limiter and phase lock loop combination as a demodulator, so that the bandwidth of the phase lock loop decreases as the carrier level decreases. The system was built for the position location and aircraft communication equipment experiment of the ATS 6 program.

Modal Analysis of Space-rocket Equipment Components

NASA Astrophysics Data System (ADS)

Igolkin, A. A.; Safin, A. I.; Prokofiev, A. B.

2018-01-01

In order to prevent vibration damage an analysis of natural frequencies and mode shapes of elements of rocket and space technology should be developed. This paper discusses technique of modal analysis on the example of the carrier platform. Modal analysis was performed by using mathematical modeling and laser vibrometer. Experimental data was clarified by using Test.Lab software. As a result of modal analysis amplitude-frequency response of carrier platform was obtained and the parameters of the elasticity was clarified.

Doping-induced change of optical properties in underdoped cuprate superconductors

NASA Astrophysics Data System (ADS)

Liu, H. L.; Quijada, M. A.; Zibold, A. M.; Yoon, Y.-D.; Tanner, D. B.; Cao, G.; Crow, J. E.; Berger, H.; Margaritondo, G.; Forró, L.; O, Beom-Hoan; Markert, J. T.; Kelly, R. J.; Onellion, M.

1999-01-01

We report on the ab-plane optical reflectance measurements of single crystals of Y-doped 0953-8984/11/1/020/img15 and Pr-doped 0953-8984/11/1/020/img16 over a wide frequency range from 80 to 0953-8984/11/1/020/img17 (10 meV-5 eV) and at temperatures between 20 and 300 K. Y and Pr doping both decrease the hole concentration in the 0953-8984/11/1/020/img18 planes. This has allowed us to investigate the evolution of ab-plane charge dynamics at doping levels ranging from heavily underdoped to nearly optimally doped. Our results of the low-frequency optical conductivity and spectral weight do not show any features associated with the normal-state pseudogap. Instead, one-component analysis for the optical conductivity shows the low-frequency depression in the scattering rate at 0953-8984/11/1/020/img19, signalling entry into the pseudogap state. Alternatively, no clear indications of the normal-state pseudogap are detected in the temperature-dependent zero-frequency free-carrier scattering rate by using two-component analysis. In the superconducting state, there is also no convincing evidence of superconducting gap absorption in all spectra. We find that there is a `universal correlation' between the numbers of carriers and the transition temperature. This correlation holds whether one considers the number of carriers in the superfluid or the total number of carriers.

Frequency and spectrum of hemoglobinopathy mutations in a Uruguayan pediatric population

PubMed Central

Luz, Julio Da; Ávila, Amalia; Icasuriaga, Sandra; Gongóra, María; Castillo, Luis; Serrón, Alejandra; Kimura, Elza Miyuki; Costa, Fernando Ferreira; Sans, Mónica; Sonati, Maria de Fátima

2013-01-01

Hemoglobinopathies are the most common recessive diseases worldwide but their prevalence in Uruguay has not been investigated. In this study, 397 unrelated outpatient children from the Pereira Rosell Hospital Center (CHPR), as well as 31 selected patients with microcytic anemia and 28 β-thalassemia carriers were analyzed for hemoglobinopathies by using biochemical and molecular biology methods. Parametric and non-parametric methods were used to compare the hematological indices between groups of genotypes. Of the 397 patients in the first group, approximately 1% (0.76% HbS and 0.25% β-thalassemia) had a mutation in the HBB gene and 3.3% had β-thalassemia. These mutations had a heterogeneous distribution that varied according to individual ancestry. HbS was found exclusively in individuals with declared African ancestry and had a carrier frequency of 2.2%. The frequency of α-thalassemia carriers in outpatients of European and African ancestry was 1.2% and 6.5%, respectively. In contrast, the frequency of α-thalassemia carriers in patients with microcytic anemia was 25.8%, significantly higher (p < 0.01) than that observed in the sample as a whole and in Afro-descendants and Euro-descendants. Significant differences were observed in the hematological parameters between individuals with thalassemia genotypes and those with a normal genotype. These results indicate that hemoglobinopathies are a relevant health problem in Uruguay. PMID:24130436

A stabilized optical frequency comb based on an Er-doped fiber femtosecond laser

NASA Astrophysics Data System (ADS)

Xia, Chuanqing; Wu, Tengfei; Zhao, Chunbo; Xing, Shuai

2018-03-01

An optical frequency comb based on a 250 MHz home-made Er-doped fiber femtosecond laser is presented in this paper. The Er-doped fiber laser has a ring cavity and operates mode-locked in femtosecond regime with the technique of nonlinear polarization rotation. The pulse duration is 118 fs and the spectral width is 30 nm. A part of the femtosecond laser is amplified in Er-doped fiber amplifier before propagating through a piece of highly nonlinear fiber for expanding the spectrum. The carrier-envelope offset frequency of the comb which has a signal-to-noise ratio more than 35 dB is extracted by means of f-2f beating. It demonstrates that both carrier-envelope offset frequency and repetition frequency keep phase locked to a Rubidium atomic clock simultaneously for 2 hours. The frequency stabilized fiber combs will be increasingly applied in optical metrology, attosecond pulse generation, and absolute distance measurement.

Design and test of a regenerative satellite transmultiplexer

NASA Astrophysics Data System (ADS)

Hung, Kenny King-Ming

1993-05-01

In a multiple access scheme for regenerative satellite communications, the bulk frequency division multiple access (FDMA) uplink signal is demodulated on board the satellite and then remodulated for time division multiplexing (TDM) downlink transmission. Conversion from frequency to time division multiplex format requires that the uplink signal be frequency demultiplexed and each individual carrier be subsequently demodulated. For thin-route application which consists of a large number of channels with fixed data rate, multicarrier demodulation can be accomplished efficiently by a digital transmultiplexer (TMUX) using a fast Fourier transform processor followed by a bank of per-channel processors. A time domain description of the TMUX algorithm is derived which elucidates how the TMUX functions. The per-channel processor performs timing and carrier recovery for optimum and coherent data detection. Timing recovery is necessarily achieved asynchronously by a filter coefficient interpolation. Carrier recovery is performed using an all-digital phase-locked loop. The combination of both timing and carrier loops is investigated for a multi-user system. The performance of the overall system is assessed over a multi-user, additive white Gaussian noise channel for a bit energy to noise power spectral density ratio down to zero dB.

Ka-Band Transponder for Deep-Space Radio Science

NASA Technical Reports Server (NTRS)

Dennis, Matthew S.; Mysoor, Narayan R.; Folkner, William M.; Mendoza, Ricardo; Venkatesan, Jaikrishna

2008-01-01

A one-page document describes a Ka-band transponder being developed for use in deep-space radio science. The transponder receives in the Deep Space Network (DSN) uplink frequency band of 34.2 to 34.7 GHz, transmits in the 31.8- to 32.3 GHz DSN downlink band, and performs regenerative ranging on a DSN standard 4-MHz ranging tone subcarrier phase-modulated onto the uplink carrier signal. A primary consideration in this development is reduction in size, relative to other such transponders. The transponder design is all-analog, chosen to minimize not only the size but also the number of parts and the design time and, thus, the cost. The receiver features two stages of frequency down-conversion. The receiver locks onto the uplink carrier signal. The exciter signal for the transmitter is derived from the same source as that used to generate the first-stage local-oscillator signal. The ranging-tone subcarrier is down-converted along with the carrier to the second intermediate frequency, where the 4-MHz tone is demodulated from the composite signal and fed into a ranging-tone-tracking loop, which regenerates the tone. The regenerated tone is linearly phase-modulated onto the downlink carrier.

A comprehensive screening program for β-thalassemia and other hemoglobinopathies in the Hooghly District of West Bengal, India, dealing with 21 137 cases.

PubMed

Bhattacharyya, Kallol Kumar; Chatterjee, Tridip; Mondal, Ujjalendu Bikash

2016-11-01

We here present a report of population screening programs (January 2012-December 2015) conducted by the Thalassemia Control Unit, Imambara Sadar Hospital, Chinsurah, Hooghly in the Hooghly District of West Bengal, India for prevention of thalassemia. We screened β-thalassemia (β-thal) heterozygotes and homozygotes, and Hb E (HBB: c.79G > A)-β-thal compound heterozygotes. Among 21 137 cases, we found 1968 heterozygotes and 192 homozygotes or compound heterozygotes. Results were evaluated with standard hematological analyses including red cell indices, hemoglobin (Hb) typing and quantification. The participants of the screening program were divided into six groups (children, pre-marriage cases, post-marital cases, family members of affected individuals, family members of carriers and pregnant women). While considering the average frequency of carriers, many reports recorded both related individuals (family members of trait and affected individuals) as well as unrelated individuals such as school children and pregnant women. These would have to be considered separately and only the unrelated individuals taken to estimate carrier frequencies in this article that would give more realistic data on carrier frequency of unrelated individuals.

Motor Carrier Safety Fitness Determination: An Improved Process

DOT National Transportation Integrated Search

1996-12-01

PREFACE This report was undertaken to define an improved process for motor carrier safety fitness determination. It was produced by the Research and Special Program Administration's (RSPA} John A. Volpe National Transportation Systems Center (the Vol...

Applications of Simulator Freeze to Carrier Guideslope Tracking Instruction. Cooperative Study Series. Final Report, May 1, 1980-August 31, 1981.

ERIC Educational Resources Information Center

Hughes, R. G.; And Others

Twenty-five experienced F-4 and F-16 Air Force pilots were instructed in carrier landings in the Visual Technology Research Simulator (VTRS). The training was conducted under three instructional conditions, two of which employed the simulator's "freeze" feature. Additionally, two methods of defining errors for carrier glideslope tracking…

47 CFR 69.104 - End user common line for non-price cap incumbent local exchange carriers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false End user common line for non-price cap... common line for non-price cap incumbent local exchange carriers. (a) This section is applicable only to incumbent local exchange carriers that are not subject to price cap regulation as that term is defined in...

Air Carrier Financial Statistics : third quarter : [2009

DOT National Transportation Integrated Search

2009-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2006

DOT National Transportation Integrated Search

2006-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : second quarter : [2013

DOT National Transportation Integrated Search

2013-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : first quarter : [2009

DOT National Transportation Integrated Search

2009-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2004

DOT National Transportation Integrated Search

2004-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : second quarter : [2008

DOT National Transportation Integrated Search

2008-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : second quarter : [2012

DOT National Transportation Integrated Search

2012-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : first quarter : [2008

DOT National Transportation Integrated Search

2008-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2003

DOT National Transportation Integrated Search

2003-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : second quarter : [2011

DOT National Transportation Integrated Search

2011-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2013

DOT National Transportation Integrated Search

2013-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2002

DOT National Transportation Integrated Search

2002-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2005

DOT National Transportation Integrated Search

2005-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : second quarter : [2012

DOT National Transportation Integrated Search

2010-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : second quarter : [2010

DOT National Transportation Integrated Search

2010-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : second quarter : [2009

DOT National Transportation Integrated Search

2009-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : first quarter : [2012

DOT National Transportation Integrated Search

2012-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2010

DOT National Transportation Integrated Search

2010-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2012

DOT National Transportation Integrated Search

2012-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : third quarter : [2011

DOT National Transportation Integrated Search

2011-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2011

DOT National Transportation Integrated Search

2011-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2007

DOT National Transportation Integrated Search

2007-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : third quarter : [2013

DOT National Transportation Integrated Search

2013-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : first quarter : [2011

DOT National Transportation Integrated Search

2011-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : first quarter : [2014

DOT National Transportation Integrated Search

2014-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : first quarter : [2013

DOT National Transportation Integrated Search

2013-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : third quarter : [2012

DOT National Transportation Integrated Search

2012-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : third quarter : [2008

DOT National Transportation Integrated Search

2008-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : first quarter : [2010

DOT National Transportation Integrated Search

2010-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2009

DOT National Transportation Integrated Search

2009-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

Air Carrier Financial Statistics : fourth quarter : [2008

DOT National Transportation Integrated Search

2008-01-01

This report presents airline financial statistics obtained from carrier reports to DOT on BTS Form 41 financial schedules. Effective with a rule (ER-1297) adopted July 1982, the filing frequency for income statement and balance sheet data was changed...

1998 NASA Review: Center for Space Telemetering and Telecommunication Systems

NASA Technical Reports Server (NTRS)

Cunningham, Garry

1998-01-01

The following topics are included in the conference proceedings following the program overview: (1) Coding and Carrier Recovery Techniques; (2) Carrier Frequency Estimation Under Unknown Doppler Shifts; (3) Small Satellite Experiments; (4) Bandwidth Efficient Modulation/Equalization Techniques.

Envelope contributions to the representation of interaural time difference in the forebrain of barn owls.

PubMed

Tellers, Philipp; Lehmann, Jessica; Führ, Hartmut; Wagner, Hermann

2017-09-01

Birds and mammals use the interaural time difference (ITD) for azimuthal sound localization. While barn owls can use the ITD of the stimulus carrier frequency over nearly their entire hearing range, mammals have to utilize the ITD of the stimulus envelope to extend the upper frequency limit of ITD-based sound localization. ITD is computed and processed in a dedicated neural circuit that consists of two pathways. In the barn owl, ITD representation is more complex in the forebrain than in the midbrain pathway because of the combination of two inputs that represent different ITDs. We speculated that one of the two inputs includes an envelope contribution. To estimate the envelope contribution, we recorded ITD response functions for correlated and anticorrelated noise stimuli in the barn owl's auditory arcopallium. Our findings indicate that barn owls, like mammals, represent both carrier and envelope ITDs of overlapping frequency ranges, supporting the hypothesis that carrier and envelope ITD-based localization are complementary beyond a mere extension of the upper frequency limit. NEW & NOTEWORTHY The results presented in this study show for the first time that the barn owl is able to extract and represent the interaural time difference (ITD) information conveyed by the envelope of a broadband acoustic signal. Like mammals, the barn owl extracts the ITD of the envelope and the carrier of a signal from the same frequency range. These results are of general interest, since they reinforce a trend found in neural signal processing across different species. Copyright © 2017 the American Physiological Society.

A low-frequency noise model with carrier generation-recombination process for pentacene organic thin-film transistor

NASA Astrophysics Data System (ADS)

Han, C. Y.; Qian, L. X.; Leung, C. H.; Che, C. M.; Lai, P. T.

2013-07-01

By including the generation-recombination process of charge carriers in conduction channel, a model for low-frequency noise in pentacene organic thin-film transistors (OTFTs) is proposed. In this model, the slope and magnitude of power spectral density for low-frequency noise are related to the traps in the gate dielectric and accumulation layer of the OTFT for the first time. The model can well fit the measured low-frequency noise data of pentacene OTFTs with HfO2 or HfLaO gate dielectric, which validates this model, thus providing an estimate on the densities of traps in the gate dielectric and accumulation layer. It is revealed that the traps in the accumulation layer are much more than those in the gate dielectric, and so dominate the low-frequency noise of pentacene OTFTs.

Coherent optical modulation for antenna remoting

NASA Technical Reports Server (NTRS)

Fitzmartin, D. J.; Gels, R. G.; Balboni, E. J.

1991-01-01

A coherent fiber optic link employing wideband frequency modulation (FM) of the optical carrier is used to transfer radio frequency (RF) or microwave signals. This system is used to link a remotely located antenna to a conveniently located electronics processing site. The advantages of coherent analog fiber optic systems over non-coherent intensity modulated fiber optic analog transmission systems are described. An optical FM link employing an indirect transmitter to frequency modulate the optical carrier and a microwave delay line discriminator receiver is described. Measured performance data for a video signal centered at 60 MHz is presented showing the use of wideband FM in the link.

The incidence of adult T-cell leukemia/lymphoma among human T-lymphotropic virus type 1 carriers in Japan.

PubMed

Satake, Masahiro; Yamada, Yasuaki; Atogami, Sunao; Yamaguchi, Kazunari

2015-06-01

Human T-lymphotropic virus type 1 (HTLV-1) is highly endemic in the Kyushu/Okinawa region of Japan. A nationwide investigation verified the frequency of HTLV-1 carriers among first-time blood donors and the occurrence of newly diagnosed adult T-cell leukemia/lymphoma (ATL) cases from 2007 through 2008. After adjusting for differences in capture rate between areas, the age-, sex- and area-specific incidence of ATL among carriers was determined. Annual ATL incidence among 10 000 carriers was 7.7 and 8.7 for the Kyushu and non-Kyushu/Okinawa regions, respectively. The incidence increased sharply for men from their 40s to their 70s, but the rate in females remained unchanged through their 40s to 70s. ATL incidence in middle-aged females was still low, even if female carrier frequency was assumed to be identical to that of males. Patients with ATL in their 60s and 70s will comprise two-thirds of all patients with ATL for the next 15 years in Japan.

Estimation of the center frequency of the highest modulation filter.

PubMed

Moore, Brian C J; Füllgrabe, Christian; Sek, Aleksander

2009-02-01

For high-frequency sinusoidal carriers, the threshold for detecting sinusoidal amplitude modulation increases when the signal modulation frequency increases above about 120 Hz. Using the concept of a modulation filter bank, this effect might be explained by (1) a decreasing sensitivity or greater internal noise for modulation filters with center frequencies above 120 Hz; and (2) a limited span of center frequencies of the modulation filters, the top filter being tuned to about 120 Hz. The second possibility was tested by measuring modulation masking in forward masking using an 8 kHz sinusoidal carrier. The signal modulation frequency was 80, 120, or 180 Hz and the masker modulation frequencies covered a range above and below each signal frequency. Four highly trained listeners were tested. For the 80-Hz signal, the signal threshold was usually maximal when the masker frequency equaled the signal frequency. For the 180-Hz signal, the signal threshold was maximal when the masker frequency was below the signal frequency. For the 120-Hz signal, two listeners showed the former pattern, and two showed the latter pattern. The results support the idea that the highest modulation filter has a center frequency in the range 100-120 Hz.

Arrays of Individually Controlled Ions Suitable for Two-Dimensional Quantum Simulations (Open Access, Publisher’s Version)

DTIC Science & Technology

2016-06-13

motional ground state, the ratio of Rabi frequencies of carrier and sideband couplings is given by the Lamb-Dicke parameter48, which is for u1 and Dkx...carrier Rabi - frequencies determine Lamb-Dicke parameters and allow for finding the orientation of modes. We use a single ion near T0 to determine the...and find corresponding coefficient settings where we obtain a maximal Rabi rate of the detection transition and/or minimal Rabi rates of micromotion

Controlling the carrier-envelope phase of Raman-generated periodic waveforms.

PubMed

Hsieh, Zhi-Ming; Lai, Chien-Jen; Chan, Han-Sung; Wu, Sih-Ying; Lee, Chao-Kuei; Chen, Wei-Jan; Pan, Ci-Ling; Yee, Fu-Goul; Kung, A H

2009-05-29

We demonstrate control of the carrier-envelope phase of ultrashort periodic waveforms that are synthesized from a Raman-generated optical frequency comb. We generated the comb by adiabatically driving a molecular vibrational coherence with a beam at a fundamental frequency plus its second harmonic. Heterodyne measurements show that full interpulse phase locking of the comb components is realized. The results set the stage for the synthesis of periodic arbitrary waveforms in the femtosecond and subfemtosecond regimes with full control.

Direct carrier-envelope phase control of an amplified laser system.

PubMed

Balčiūnas, Tadas; Flöry, Tobias; Baltuška, Andrius; Stanislauskas, Tomas; Antipenkov, Roman; Varanavičius, Arūnas; Steinmeyer, Günter

2014-03-15

Direct carrier-envelope phase stabilization of an Yb:KGW MOPA laser system is demonstrated with a residual phase jitter reduced to below 100 mrad, which compares favorably with previous stabilization reports, both of amplified laser systems as well as of ytterbium-based oscillators. This novel stabilization scheme relies on a frequency synthesis scheme and a feed-forward approach. The direct stabilization of a sub-MHz frequency comb from a CPA amplifier not only reduces the phase noise but also greatly simplifies the stabilization setup.

Low Computational Signal Acquisition for GNSS Receivers Using a Resampling Strategy and Variable Circular Correlation Time

PubMed Central

Zhang, Yeqing; Wang, Meiling; Li, Yafeng

2018-01-01

For the objective of essentially decreasing computational complexity and time consumption of signal acquisition, this paper explores a resampling strategy and variable circular correlation time strategy specific to broadband multi-frequency GNSS receivers. In broadband GNSS receivers, the resampling strategy is established to work on conventional acquisition algorithms by resampling the main lobe of received broadband signals with a much lower frequency. Variable circular correlation time is designed to adapt to different signal strength conditions and thereby increase the operation flexibility of GNSS signal acquisition. The acquisition threshold is defined as the ratio of the highest and second highest correlation results in the search space of carrier frequency and code phase. Moreover, computational complexity of signal acquisition is formulated by amounts of multiplication and summation operations in the acquisition process. Comparative experiments and performance analysis are conducted on four sets of real GPS L2C signals with different sampling frequencies. The results indicate that the resampling strategy can effectively decrease computation and time cost by nearly 90–94% with just slight loss of acquisition sensitivity. With circular correlation time varying from 10 ms to 20 ms, the time cost of signal acquisition has increased by about 2.7–5.6% per millisecond, with most satellites acquired successfully. PMID:29495301

Low Computational Signal Acquisition for GNSS Receivers Using a Resampling Strategy and Variable Circular Correlation Time.

PubMed

Zhang, Yeqing; Wang, Meiling; Li, Yafeng

2018-02-24

For the objective of essentially decreasing computational complexity and time consumption of signal acquisition, this paper explores a resampling strategy and variable circular correlation time strategy specific to broadband multi-frequency GNSS receivers. In broadband GNSS receivers, the resampling strategy is established to work on conventional acquisition algorithms by resampling the main lobe of received broadband signals with a much lower frequency. Variable circular correlation time is designed to adapt to different signal strength conditions and thereby increase the operation flexibility of GNSS signal acquisition. The acquisition threshold is defined as the ratio of the highest and second highest correlation results in the search space of carrier frequency and code phase. Moreover, computational complexity of signal acquisition is formulated by amounts of multiplication and summation operations in the acquisition process. Comparative experiments and performance analysis are conducted on four sets of real GPS L2C signals with different sampling frequencies. The results indicate that the resampling strategy can effectively decrease computation and time cost by nearly 90-94% with just slight loss of acquisition sensitivity. With circular correlation time varying from 10 ms to 20 ms, the time cost of signal acquisition has increased by about 2.7-5.6% per millisecond, with most satellites acquired successfully.

47 CFR 80.383 - Vessel Traffic Services (VTS) system frequencies.

Code of Federal Regulations, 2012 CFR

2012-10-01

... protection areas provided there is no interference to VTS communications within the VTS areas. [51 FR 31213... geographic radio protected areas. (a) Assigned frequencies: Vessel Traffic Control Frequencies Carrier frequencies (MHz) Geographic areas 156.250 Seattle. 156.550 New York, New Orleans, 2 Houston, Prince William...

47 CFR 80.383 - Vessel Traffic Services (VTS) system frequencies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... protection areas provided there is no interference to VTS communications within the VTS areas. [51 FR 31213... geographic radio protected areas. (a) Assigned frequencies: Vessel Traffic Control Frequencies Carrier frequencies (MHz) Geographic areas 156.250 Seattle. 156.550 New York, New Orleans, 2 Houston, Prince William...

47 CFR 80.383 - Vessel Traffic Services (VTS) system frequencies.

Code of Federal Regulations, 2013 CFR

2013-10-01

... protection areas provided there is no interference to VTS communications within the VTS areas. [51 FR 31213... geographic radio protected areas. (a) Assigned frequencies: Vessel Traffic Control Frequencies Carrier frequencies (MHz) Geographic areas 156.250 Seattle. 156.550 New York, New Orleans, 2 Houston, Prince William...

47 CFR 80.383 - Vessel Traffic Services (VTS) system frequencies.

Code of Federal Regulations, 2014 CFR

2014-10-01

... protection areas provided there is no interference to VTS communications within the VTS areas. [51 FR 31213... geographic radio protected areas. (a) Assigned frequencies: Vessel Traffic Control Frequencies Carrier frequencies (MHz) Geographic areas 156.250 Seattle. 156.550 New York, New Orleans, 2 Houston, Prince William...

47 CFR 80.383 - Vessel Traffic Services (VTS) system frequencies.

Code of Federal Regulations, 2011 CFR

2011-10-01

... protection areas provided there is no interference to VTS communications within the VTS areas. [51 FR 31213... geographic radio protected areas. (a) Assigned frequencies: Vessel Traffic Control Frequencies Carrier frequencies (MHz) Geographic areas 156.250 Seattle. 156.550 New York, New Orleans, 2 Houston, Prince William...

Optimum Detection Of Slow-Frequency-Hopping Signals

NASA Technical Reports Server (NTRS)

Levitt, Barry K.; Cheng, Unjeng

1994-01-01

Two papers present theoretical analyses of various schemes for coherent and noncoherent detection of M-ary-frequency-shift-keyed (MFSK) signals with slow frequency hopping. Special attention focused on continuous-phase-modulation (CPM) subset of SFH/MFSK signals, for which frequency modulation such carrier phase remains continuous (albeit unknown) during each hop.

47 CFR 22.863 - Frequency stability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Frequency stability. 22.863 Section 22.863 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.863 Frequency stability. The...

47 CFR 1.10014 - What happens after officially filing my application?

Code of Federal Regulations, 2013 CFR

2013-10-01

... Frequency IHF-xxxxx. Recognized Operating Agency ROA-xxxxx. Satellite Space Station SAT-xxxxx. Satellite... PN released. International High Frequency IHF-xxxxx. Recognized Operating Agency No action taken PN... Carrier Affiliation Notification. International High Frequency: Construction Permits, Licenses...

47 CFR 1.10014 - What happens after officially filing my application?

Code of Federal Regulations, 2014 CFR

2014-10-01

... Frequency IHF-xxxxx. Recognized Operating Agency ROA-xxxxx. Satellite Space Station SAT-xxxxx. Satellite... PN released. International High Frequency IHF-xxxxx. Recognized Operating Agency No action taken PN... Carrier Affiliation Notification. International High Frequency: Construction Permits, Licenses...

47 CFR 1.10014 - What happens after officially filing my application?

Code of Federal Regulations, 2012 CFR

2012-10-01

... Frequency IHF-xxxxx. Recognized Operating Agency ROA-xxxxx. Satellite Space Station SAT-xxxxx. Satellite... PN released. International High Frequency IHF-xxxxx. Recognized Operating Agency No action taken PN... Carrier Affiliation Notification. International High Frequency: Construction Permits, Licenses...

47 CFR 80.375 - Radiodetermination frequencies.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SERVICES STATIONS IN THE MARITIME SERVICES Frequencies Radiodetermination § 80.375 Radiodetermination... direction finding radar stations will be authorized on land. (a) Direction finding frequencies. The carrier... usage must comply with the following requirements: (1) They are not permitted within the territorial...

47 CFR 80.375 - Radiodetermination frequencies.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SERVICES STATIONS IN THE MARITIME SERVICES Frequencies Radiodetermination § 80.375 Radiodetermination... direction finding radar stations will be authorized on land. (a) Direction finding frequencies. The carrier... usage must comply with the following requirements: (1) They are not permitted within the territorial...

47 CFR 80.375 - Radiodetermination frequencies.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SERVICES STATIONS IN THE MARITIME SERVICES Frequencies Radiodetermination § 80.375 Radiodetermination... direction finding radar stations will be authorized on land. (a) Direction finding frequencies. The carrier... usage must comply with the following requirements: (1) They are not permitted within the territorial...

47 CFR 54.604 - Existing contracts.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Universal Service Support for Health Care Providers § 54.604 Existing contracts. (a) Existing... health care provider as defined under § 54.601 and a telecommunications carrier shall be exempt from the...

Light tuning DC and AC electrical properties of ZnO-rGO based hybrid nanocomposite film

NASA Astrophysics Data System (ADS)

Nath, Debarati; Mandal, S. K.; Deb, Debajit; Rakshit, J. K.; Dey, P.; Roy, J. N.

2018-03-01

We have investigated the electrical and optoelectrical properties of a zinc oxide (ZnO):reduced graphene oxide (rGO) nanocomposite film prepared through the sol gel process on a glass substrate under dark and illumination conditions of light. The bandgap of the composite film is decreased from the pure ZnO nanofilm due to the formation of a Zn-O-C bond in the composite film. The linear behavior in the Current-Voltage curve is attributed to Ohmic contact between ZnO and rGO grains. The photocurrent of the composite film is found to increase with an increase in light intensity having two different slopes, indicating an enhancement of the mobility of carriers and dissociation rate of excitons. The observed decrement of the impedance value with the intensity of light may be due to the flow of charge carriers and the presence of the light dependent relaxation process in the system. Nyquist plots have been fitted using a parallel combination of grain boundary resistances and grain boundary capacitance at different intensities of light. The relaxation frequency is observed to shift towards the high frequency regime. Carrier transit time has been calculated from relaxation frequency showing opposite behavior with the intensity of light. These results indicate the higher generations of photogenerated carriers at the interface between rGO and ZnO grains and an enhancement of the charge transport process due to the increment of the mobility of charge carriers in the system.

Genetic analysis of the M2/ANXA5 haplotype as recurrent pregnancy loss predisposition in the Malay population.

PubMed

Ang, Kai-Cheen; Kathirgamanathan, Sushilnathan; Ch'ng, Ewe Seng; Lee, Yan-Yeow; Roslani, Anna-Liza; Naidu, Bavanandan; Kumar, Krishna; Abdullah, Ridzuan; Kadir, Siti-Nadiah Abdul; Yusoff, Narazah Mohd; Abdullah, Wan Zaidah; Bogdanova, Nadja; Wieacker, Peter; Markoff, Arseni; Tang, Thean-Hock

2017-04-01

The aim of this study was to evaluate a new predisposition factor, M2/ANXA5 (RPRGL3), in recurrent pregnancy loss (RPL) patients of Malay origin, since it was previously known that the prevalence of this condition is relatively high among the Malay population of Malaysia, where conventional hereditary thrombophilia factors have been generally ruled out. A total of 232 women who had experienced ≥2 unexplained RPL and 141 available male partners were recruited, with 360 healthy Malay and 166 parous female controls. Prevalence of M2 carriage and RPL odds ratios were calculated in (a) control and patient groups; (b) clinically defined subgroups in categories of pregnancy loss, primary, secondary, and tertiary; and (c) timing of pregnancy loss in early, ≤15th gestation week and "late" fetal losses, and >15th gestation week subgroups. Both male and female subjects had similar M2/ANXA5 allele frequencies. The carrier rate of M2/ANXA5 for the general Malay population was 42.2 and 34.9% for parous controls. These carrier rates compared to Malay RPL subjects (52% M2 carriers) resulted in elevated odds ratios (95% confidence interval) of 1.53 (1.1 to 2.1) and 1.97 (1.3 to 3.1) accordingly for early fetal losses. Moreover, exceeding copy numbers of M2/ANXA5 alleles seemed to afflict a greater chance of RPL in couples, especially when both partners were M2 carriers. This study confirmed the proposed role of M2/ANXA5 as embryonic, genetically associated thrombophilia predisposition factor for early RPL among ethnic Malay of Malaysia.

Decision feedback loop for tracking a polyphase modulated carrier

NASA Technical Reports Server (NTRS)

Simon, M. K. (Inventor)

1974-01-01

A multiple phase modulated carrier tracking loop for use in a frequency shift keying system is described in which carrier tracking efficiency is improved by making use of the decision signals made on the data phase transmitted in each T-second interval. The decision signal is used to produce a pair of decision-feedback quadrature signals for enhancing the loop's performance in developing a loop phase error signal.

Carrier-envelope phase control by a composite plate.

PubMed

Ell, Richard; Birge, Jonathan R; Araghchini, Mohammad; Kärtner, Franz X

2006-06-12

We demonstrate a new concept to vary the carrier-envelope phase of a mode-locked laser by a composite plate while keeping all other pulse parameters practically unaltered. The effect is verified externally in an interferometric autocorrelator, as well as inside the cavity of an octave-spanning femtosecond oscillator. The carrier-envelope frequency can be shifted by half the repetition rate with negligible impact on pulse spectrum and energy.

Temperature feedback control for long-term carrier-envelope phase locking.

PubMed

Yun, Chenxia; Chen, Shouyuan; Wang, He; Chini, Michael; Chang, Zenghu

2009-09-20

We report a double feedback loop for the improvement of the carrier-envelope phase stabilization of a chirped mirror based femtosecond laser oscillator. By combining the control of the Ti:sapphire crystal temperature and the modulation of the pump power, the carrier envelope offset frequency, fCEO, was locked for close to 20 h, which is much longer than the typical phase stabilization time with only pump power modulation.

Frequency and Clinicopathological Characteristics of Presenilin 1 Gly206Ala Mutation in Puerto Rican Hispanics with Dementia

PubMed Central

Arnold, Steven E.; Vega, Irving E.; Karlawish, Jason H.; WoIk, David A.; Nunez, Jessica; Negron, Mirna; Xie, Sharon X.; Wang, Li-San; Dubroff, Jacob G.; McCarty-Wood, Elisabeth; Trojanowski, John Q.; Van Deerlin, Vivianna

2012-01-01

The frequency and clinical and pathological characteristics associated with the Gly206Ala presenilin 1 (PSEN1) mutation in Puerto Rican and non-Puerto Rican Hispanics were evaluated at the University of Pennsylvania’s Alzheimer’s Disease Center. DNAs from all cohort subjects were genotyped for the Gly206Ala PSEN1 mutation. Carriers and non-carriers with neurodegenerative disease dementias were compared for demographic, clinical, psychometric, and biomarker variables. Nineteen (12.6%) of 151 unrelated subjects with dementia were discovered to carry the PSEN1 Gly 206Ala mutation. Microsatellite marker genotyping determined a common ancestral haplotype for all carriers. Carriers were all of Puerto Rican heritage with significantly younger age of onset, but otherwise were clinically and neuropsychologically comparable to those of non-carriers with AD. Three subjects had extensive topographic and biochemical biomarker assessments that were also typical of non-carriers with AD. Neuropathological examination in one subject revealed severe, widespread plaque and tangle pathology without other meaningful disease lesions. The PSEN1 Gly206Ala mutation is notably frequent in unrelated Puerto Rican immigrants with dementia in Philadelphia. Considered together with the increased prevalence and mortality of AD reported in Puerto Rico, these high rates may reflect hereditary risk concentrated in the island which warrants further study. PMID:23114514

Auger heating of carriers in {GaAs}/{AlAs} heterostructures

NASA Astrophysics Data System (ADS)

Borri, P.; Ceccherini, S.; Gurioli, M.; Bogani, F.

1997-07-01

The photoluminescence of {GaAs}/{AlAs} multiple quantum wells structures under optical ps excitation is investigated for carrier densities in the range 10 18-4 × 10 19 cm -3 with frequency and time-resolved spectroscopic techniques. The measurements give a direct evidence of the occurrence in the sample of carrier heating. This energy up-conversion gives rise to photoluminescence from the states near the Fermi level whose intensity and time evolution depend on the carrier density in a strongly non-linear way. The observed behaviour can be explained introducing in the carrier dynamics an up-conversion mechanism due to Auger-like processes.

Pulse width modulation inverter with battery charger

DOEpatents

Slicker, James M.

1985-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Pulse width modulation inverter with battery charger

NASA Technical Reports Server (NTRS)

Slicker, James M. (Inventor)

1985-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

Effects of trap density on drain current LFN and its model development for E-mode GaN MOS-HEMT

NASA Astrophysics Data System (ADS)

Panda, D. K.; Lenka, T. R.

2017-12-01

In this paper the drain current low-frequency noise (LFN) of E-mode GaN MOS-HEMT is investigated for different gate insulators such as SiO2, Al2O3/Ga2O3/GdO3, HfO2/SiO2, La2O3/SiO2 and HfO2 with different trap densities by IFM based TCAD simulation. In order to analyze this an analytical model of drain current low frequency noise is developed. The model is developed by considering 2DEG carrier fluctuations, mobility fluctuations and the effects of 2DEG charge carrier fluctuations on the mobility. In the study of different gate insulators it is observed that carrier fluctuation is the dominant low frequency noise source and the non-uniform exponential distribution is critical to explain LFN behavior, so the analytical model is developed by considering uniform distribution of trap density. The model is validated with available experimental data from literature. The effect of total number of traps and gate length scaling on this low frequency noise due to different gate dielectrics is also investigated.

A protective effect of the BDNF Met/Met genotype in obesity in healthy Caucasian subjects but not in patients with coronary heart disease.

PubMed

Sustar, A; Nikolac Perkovic, M; Nedic Erjavec, G; Svob Strac, D; Pivac, N

2016-08-01

Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor with an important role in the regulation of body weight, body mass index (BMI) and obesity. Increased BMI that leads to obesity is a substantial risk factor for coronary heart disease (CHD). The functional BDNF Val66Met polymorphism (rs6265) has been associated with CHD, obesity and BMI. The aim of the study was to determine the association between BDNF rs6265 polymorphism and CHD and/or BMI in patients with CHD and healthy control subjects. The study included 704 Caucasian subjects: 206 subjects with CHD and 498 healthy control subjects. The BDNF rs6265 genotype frequency was similar in male and female subjects, and there were no differences in the frequency of the BDNF rs6265 genotypes in 206 patients with CHD and in 498 healthy subjects. When study participants were subdivided according to the BMI categories into normal weight, overweight and obese subjects, significantly different BDNF rs6265 genotype frequency was found within healthy subjects, but not within patients with CHD. Healthy subjects, but not patients with CHD, subdivided into carriers of the Met/Met, Met/Val and Val/Val genotype, had different BMI scores. The BDNF rs6265 genotype frequency was similar in male and female subjects, and there were no differences in the frequency of the BDNF rs6265 genotypes in 206 patients with CHD and in 498 healthy subjects. When study participants were subdivided according to the BMI categories into normal weight, overweight and obese subjects, significantly different BDNF rs6265 genotype frequency was found within healthy subjects, but not within patients with CHD. Healthy subjects, but not patients with CHD, subdivided into carriers of the Met/Met, Met/Val and Val/Val genotype, had different BMI scores. BDNF rs6265 polymorphism was not associated with a diagnosis of CHD or with BMI categories among patients with CHD. In contrast, healthy Caucasians, carriers of the BDNF Met/Met genotype, had more frequently normal weight compared to carriers of other BDNF genotypesBDNF rs6265 polymorphism was not associated with a diagnosis of CHD or with BMI categories among patients with CHD. In contrast, healthy Caucasians, carriers of the BDNF Met/Met genotype, had more frequently normal weight compared to carriers of other BDNF genotypes. BDNF rs6265 polymorphism is associated with BMI categories, and the BDNF Met/Met genotype has a protective role in obesity in healthy subjects, while this effect was not present in patients with CHD.

Time delay and distance measurement

NASA Technical Reports Server (NTRS)

Abshire, James B. (Inventor); Sun, Xiaoli (Inventor)

2011-01-01

A method for measuring time delay and distance may include providing an electromagnetic radiation carrier frequency and modulating one or more of amplitude, phase, frequency, polarization, and pointing angle of the carrier frequency with a return to zero (RZ) pseudo random noise (PN) code. The RZ PN code may have a constant bit period and a pulse duration that is less than the bit period. A receiver may detect the electromagnetic radiation and calculate the scattering profile versus time (or range) by computing a cross correlation function between the recorded received signal and a three-state RZ PN code kernel in the receiver. The method also may be used for pulse delay time (i.e., PPM) communications.

A proposed technique for the Venus balloon telemetry and Doppler frequency recovery

NASA Technical Reports Server (NTRS)

Jurgens, R. F.; Divsalar, D.

1985-01-01

A technique is proposed to accurately estimate the Doppler frequency and demodulate the digitally encoded telemetry signal that contains the measurements from balloon instruments. Since the data are prerecorded, one can take advantage of noncausal estimators that are both simpler and more computationally efficient than the usual closed-loop or real-time estimators for signal detection and carrier tracking. Algorithms for carrier frequency estimation subcarrier demodulation, bit and frame synchronization are described. A Viterbi decoder algorithm using a branch indexing technique has been devised to decode constraint length 6, rate 1/2 convolutional code that is being used by the balloon transmitter. These algorithms are memory efficient and can be implemented on microcomputer systems.

Generation of tunable, high repetition rate optical frequency combs using on-chip silicon modulators

NASA Astrophysics Data System (ADS)

Nagarjun, K. P.; Jeyaselvan, Vadivukarassi; Selvaraja, Shankar Kumar; Supradeepa, V. R.

2018-04-01

We experimentally demonstrate tunable, highly-stable frequency combs with high repetition-rates using a single, charge injection based silicon PN modulator. In this work, we demonstrate combs in the C-band with over 8 lines in a 20-dB bandwidth. We demonstrate continuous tuning of the center frequency in the C-band and tuning of the repetition-rate from 7.5GHz to 12.5GHz. We also demonstrate through simulations the potential for bandwidth scaling using an optimized silicon PIN modulator. We find that, the time varying free carrier absorption due to carrier injection, an undesirable effect in data modulators, assists here in enhancing flatness in the generated combs.

Re-entry of the Soyuz MS-08 carrier rocket 25 March 2018

NASA Astrophysics Data System (ADS)

Stomeo, Enrico

2018-03-01

The re-entry of the Soyuz MS-08 carrier rocket on 2018 March 25 could be observed from a large part of the central Mediterranean Sea. The radio station of the Planetarium in Venice was able to record the return into the atmosphere. The radio signal was perceived in Venice from 01h23m52,5s UTC with a frequency of 1431,363 Hz until 01h24m02,0s with a frequency of 805,487 Hz. Considering the recorded frequency variations due to the Doppler effect, it can be deduced that the object was drastically decelerating in those last moments by about 1.3 km/s.

Experimental observation of carrier-envelope-phase effects by multicycle pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jha, Pankaj K.; Scully, Marlan O.; Mechanical and Aerospace Engineering and the Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544

2011-03-15

We present an experimental and theoretical study of carrier-envelope-phase (CEP) effects on the population transfer between two bound atomic states interacting with pulses consisting of many cycles. Using intense radio-frequency pulse with Rabi frequency of the order of the atomic transition frequency, we investigate the influence of the CEP on the control of phase-dependent multiphoton transitions between the Zeeman sublevels of the ground state of {sup 87}Rb. Our scheme has no limitation on the duration of the pulses. Extending the CEP control to longer pulses creates interesting possibilities to generate pulses with accuracy that is better than the period ofmore » optical oscillations.« less

Effects of surface nanostructuring and impurity doping on ultrafast carrier dynamics of silicon photovoltaic cells: a pump-probe study

NASA Astrophysics Data System (ADS)

Chen, Tianyu; Nam, Yoon-Ho; Wang, Xinke; Han, Peng; Sun, Wenfeng; Feng, Shengfei; Ye, Jiasheng; Song, Jae-Won; Lee, Jung-Ho; Zhang, Chao; Zhang, Yan

2018-01-01

We present femtosecond optical pump-terahertz probe studies on the ultrafast dynamical processes of photo-generated charge carriers in silicon photovoltaic cells with various nanostructured surfaces and doping densities. The pump-probe measurements provide direct insight on the lifetime of photo-generated carriers, frequency-dependent complex dielectric response along with photoconductivity of silicon photovoltaic cells excited by optical pump pulses. A lifetime of photo-generated carriers of tens of nanosecond is identified from the time-dependent pump-induced attenuation of the terahertz transmission. In addition, we find a large value of the imaginary part of the dielectric function and of the real part of the photoconductivity in silicon photovoltaic cells with micron length nanowires. We attribute these findings to the result of defect-enhanced electron-photon interactions. Moreover, doping densities of phosphorous impurities in silicon photovoltaic cells are also quantified using the Drude-Smith model with our measured frequency-dependent complex photoconductivities.

Efficient algorithms for solution of interference cancellation and channel estimation for mobile OFDM system

NASA Astrophysics Data System (ADS)

Fan, Tong-liang; Wen, Yu-cang; Kadri, Chaibou

Orthogonal frequency-division multiplexing (OFDM) is robust against frequency selective fading because of the increase of the symbol duration. However, the time-varying nature of the channel causes inter-carrier interference (ICI) which destroys the orthogonal of sub-carriers and degrades the system performance severely. To alleviate the detrimental effect of ICI, there is a need for ICI mitigation within one OFDM symbol. We propose an iterative Inter-Carrier Interference (ICI) estimation and cancellation technique for OFDM systems based on regularized constrained total least squares. In the proposed scheme, ICI aren't treated as additional additive white Gaussian noise (AWGN). The effect of Inter-Carrier Interference (ICI) and inter-symbol interference (ISI) on channel estimation is regarded as perturbation of channel. We propose a novel algorithm for channel estimation o based on regularized constrained total least squares. Computer simulations show that significant improvement can be obtained by the proposed scheme in fast fading channels.

Carrier screening of RTEL1 mutations in the Ashkenazi Jewish population.

PubMed

Fedick, A M; Shi, L; Jalas, C; Treff, N R; Ekstein, J; Kornreich, R; Edelmann, L; Mehta, L; Savage, S A

2015-08-01

Hoyeraal-Hreidarsson syndrome (HH) is a clinically severe variant of dyskeratosis congenita (DC), characterized by cerebellar hypoplasia, microcephaly, intrauterine growth retardation, and severe immunodeficiency in addition to features of DC. Germline mutations in the RTEL1 gene have recently been identified as causative of HH. In this study, the carrier frequency for five RTEL1 mutations that occurred in individuals of Ashkenazi Jewish descent was investigated in order to advise on including them in existing clinical mutation panels for this population. Our screening showed that the carrier frequency for c.3791G>A (p.R1264H) was higher than expected, 1% in the Ashkenazi Orthodox and 0.45% in the general Ashkenazi Jewish population. Haplotype analyses suggested the presence of a common founder. We recommend that the c.3791G>A RTEL1 mutation be considered for inclusion in carrier screening panels in the Ashkenazi population. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Thickness-dependent carrier mobility of ambipolar MoTe2: Interplay between interface trap and Coulomb scattering

NASA Astrophysics Data System (ADS)

Ji, Hyunjin; Lee, Gwanmu; Joo, Min-Kyu; Yun, Yoojoo; Yi, Hojoon; Park, Ji-Hoon; Suh, Dongseok; Lim, Seong Chu

2017-05-01

The correlation between the channel thickness and the carrier mobility is investigated by conducting static and low frequency (LF) noise characterization for ambipolar carriers in multilayer MoTe2 transistors. For channel thicknesses in the range of 5-15 nm, both the low-field carrier mobility and the Coulomb-scattering-limited carrier mobility (μC) are maximal at a thickness of ˜10 nm. For LF noise, the interplay of interface trap density (NST), which was minimal at ˜10 nm, and the interfacial Coulomb scattering parameter (αSC), which decreased up to 10 nm and saturated above 10 nm, explained the mobility (μC) peaked near 10 nm by the carrier fluctuation and charge distribution.

Ground Isolation Circuit for Isolating a Transmission Line from Ground Interference

NASA Technical Reports Server (NTRS)

Davidson, Craig A. (Inventor)

1996-01-01

This invention relates generally to a system for isolating ground interference from a transmission line, e.g., a ground isolation circuit for isolating a wideband transmission signal (such as a video signal) from ground by modulating the base signal on a carrier signal to permit the transmission signal to be isolated. In one embodiment, the circuit includes a pair of matched mixer circuits, each of which receives a carrier signal from the same oscillator circuit. The first mixer circuit also receives the baseband signal input, after appropriate conditioning, and modulates the baseband signal onto the carrier signal. In a preferred embodiment the carrier signal has a predetermined frequency which is at least two times the frequency of the baseband signal. The modulated signal (which can comprise an rf signal) is transmitted via an rf transmission line to the second mixer, which demodulates the rf signal to recover the baseband signal. Each port of the mixer connects to an isolation transformer to ensure isolation from ground interference. The circuit is considered to be of commercial value in that it can provide isolation between transmitting and receiving circuits, e.g., ground isolation for television circuits or high frequency transmitters, without the need for video transformers or optical isolators, thereby reducing the complexity, power consumption, and weight of the system.

Expansion of epicyclic gear dynamic analysis program

NASA Technical Reports Server (NTRS)

Boyd, Linda Smith; Pike, James A.

1987-01-01

The multiple mesh/single stage dynamics program is a gear tooth analysis program which determines detailed geometry, dynamic loads, stresses, and surface damage factors. The program can analyze a variety of both epicyclic and single mesh systems with spur or helical gear teeth including internal, external, and buttress tooth forms. The modifications refine the options for the flexible carrier and flexible ring gear rim and adds three options: a floating Sun gear option; a natural frequency option; and a finite element compliance formulation for helical gear teeth. The option for a floating Sun incorporates two additional degrees of freedom at the Sun center. The natural frequency option evaluates the frequencies of planetary, star, or differential systems as well as the effect of additional springs at the Sun center and those due to a flexible carrier and/or ring gear rim. The helical tooth pair finite element calculated compliance is obtained from an automated element breakup of the helical teeth and then is used with the basic gear dynamic solution and stress postprocessing routines. The flexible carrier or ring gear rim option for planetary and star spur gear systems allows the output torque per carrier and ring gear rim segment to vary based on the dynamic response of the entire system, while the total output torque remains constant.

47 CFR 73.682 - TV transmission standards.

Code of Federal Regulations, 2012 CFR

2012-10-01

....682 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO... frequency shall be nominally 1.25 MHz above the lower boundary of the channel. (3) The aural center frequency shall be 4.5 MHz higher than the visual carrier frequency. (4) The visual transmission amplitude...

47 CFR 73.682 - TV transmission standards.

Code of Federal Regulations, 2011 CFR

2011-10-01

....682 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO... frequency shall be nominally 1.25 MHz above the lower boundary of the channel. (3) The aural center frequency shall be 4.5 MHz higher than the visual carrier frequency. (4) The visual transmission amplitude...

47 CFR 73.682 - TV transmission standards.

Code of Federal Regulations, 2013 CFR

2013-10-01

....682 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO... frequency shall be nominally 1.25 MHz above the lower boundary of the channel. (3) The aural center frequency shall be 4.5 MHz higher than the visual carrier frequency. (4) The visual transmission amplitude...

47 CFR 73.682 - TV transmission standards.

Code of Federal Regulations, 2014 CFR

2014-10-01

....682 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO... frequency shall be nominally 1.25 MHz above the lower boundary of the channel. (3) The aural center frequency shall be 4.5 MHz higher than the visual carrier frequency. (4) The visual transmission amplitude...

47 CFR 73.682 - TV transmission standards.

Code of Federal Regulations, 2010 CFR

2010-10-01

....682 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO... frequency shall be nominally 1.25 MHz above the lower boundary of the channel. (3) The aural center frequency shall be 4.5 MHz higher than the visual carrier frequency. (4) The visual transmission amplitude...

Ultra-wideband microwave photonic frequency downconverter based on carrier-suppressed single-sideband modulation

NASA Astrophysics Data System (ADS)

Wang, Yunxin; Li, Jingnan; Wang, Dayong; Zhou, Tao; Xu, Jiahao; Zhong, Xin; Yang, Dengcai; Rong, Lu

2018-03-01

An ultra-wideband microwave photonic frequency downconverter is proposed based on carrier-suppressed single-sideband (CS-SSB) modulation. A radio frequency (RF) signal and a local oscillator (LO) signal are combined to drive a dual-parallel Mach-Zehnder modulator (DPMZM) through the electrical 90°hybrid coupler. To break through the bandwidth limit, an optical bandpass filter (OBPF) is applied simultaneously. Then a photodetector (PD) after OBPF is used to obtain intermediate frequency (IF) signal. Experimental results demonstrate that the proposed frequency downconverter can generate the CS-SSB modulation signal from 2 to 40 GHz in optical spectrum. All the mixing spurs are completely suppressed under the noise floor in electrical spectrum, and the output IF signal possesses high purity with a suppression ratio of the undesired signals (≥40 dB). Furthermore, the multi-octave downconversion can also be implemented to satisfy the bandwidth requirement of multi-channel communication. The proposed frequency downconverter supplies an ultra-wideband and high-purity alternative for the signal processing in microwave photonic applications.

Channel Equalization for Single Carrier MIMO Underwater Acoustic Communications

DTIC Science & Technology

2010-01-01

II Tx 1 Tx 2 Symbol mapping s1 s2 x1 x2 sa Figure 2: Signalling at the transmitter in Makai05 experiment. fc = 32 kHz and the symbol interval was...frequency was fc = 37.5 kHz and the symbol interval was 0.05ms. The occupied channel bandwidth was fb = 25 kHz due to a pulse shaping filter with roll...water. QPSK modulation was used with a symbol rate of 4 ksps. The carrier frequency was fc = 17 kHz. The structure of the transmission packet is

Flexible, polymer gated, AC-driven organic electroluminescence devices

NASA Astrophysics Data System (ADS)

Xu, Junwei; Carroll, David L.

2017-08-01

Comparing rigid inorganic layer, polymeric semiconducting gate layer exhibits superior flexibility as well as efficient carrier manipulation in high frequency AC cycles. Mechanism of the carrier manipulation at the gate in forward and reversed bias of AC cycle is studied. The flexible PET-based AC-OEL device with poly[(9,9-bis(3'-((N,N-dimethyl)-Nethylammonium)- propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN-Br) gate shows a stable electroluminescent performance in frequency sweep with a color rendering index (CRI) over 81 at 2800K color temperature.

Comparison of FDMA and CDMA for second generation land-mobile satellite communications

NASA Technical Reports Server (NTRS)

Yongacoglu, A.; Lyons, R. G.; Mazur, B. A.

1990-01-01

Code Division Multiple Access (CDMA) and Frequency Division Multiple Access (FDMA) (both analog and digital) systems capacities are compared on the basis of identical link availabilities and physical propagation models. Parameters are optimized for a bandwidth limited, multibeam environment. For CDMA, the benefits of voice activated carriers, antenna discrimination, polarization reuse, return link power control and multipath suppression are included in the analysis. For FDMA, the advantages of bandwidth efficient modulation/coding combinations, voice activated carriers, polarization reuse, beam placement, and frequency staggering were taken into account.

Terahertz Oscillations of Hot Electrons in Graphene

DTIC Science & Technology

2015-01-01

half the frequency ?F = 2?eF/~?OP , where 2?/?F is the time taken for carriers to accelerate ballistically to the optic phonon...resonance. Such resonance occurs at about half the frequency ωF = 2πeF/~ωOP , where 2π/ωF is the time taken for carriers to accelerate ballistically to the ... The current density on the plane is given by, Jx(t) = −4evF ∑ ~k f(~k, t) cos(φ), (2.16) where φ is the angle between ~k and the kx axis. Figure

Prevalence of combinatorial CYP2C9 and VKORC1 genotypes in Puerto Ricans: implications for warfarin management in Hispanics.

PubMed

Duconge, Jorge; Cadilla, Carmen L; Windemuth, Andreas; Kocherla, Mohan; Gorowski, Krystyna; Seip, Richard L; Bogaard, Kali; Renta, Jessica Y; Piovanetti, Paola; D'Agostino, Darrin; Santiago-Borrero, Pedro J; Ruaño, Gualberto

2009-01-01

Polymorphisms in the cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) genes significantly alter the effective warfarin dose. We determined the frequencies of alleles, single carriers, and double carriers of single nucleotide polymorphisms (SNPs) in the CYP2C9 and VKORC1 genes in a Puerto Rican cohort and gauged the impact of these polymorphisms on warfarin dosage using a published algorithm. A total of 92 DNA samples were genotyped using Luminex x-MAP technology. The polymorphism frequencies were 6.52%, 5.43% and 28.8% for CYP2C9 *2, *3 and VKORC1-1639 C>A polymorphisms, respectively. The prevalence of combinatorial genotypes was 16% for carriers of both the CYP2C9 and VKORC1 polymorphisms, 9% for carriers of CYP2C9 polymorphisms, 35% for carriers of the VKORC1 polymorphism, and the remaining 40% were non-carriers for either gene. Based on a published warfarin dosing algorithm, single, double and triple carriers of functionally deficient polymorphisms predict reductions of 1.0-1.6, 2.0-2.9, and 2.9-3.7 mg/day, respectively, in warfarin dose. Overall, 60% of the population carried at least a single polymorphism predicting deficient warfarin metabolism or responsiveness and 13% were double carriers with polymorphisms in both genes studied. Combinatorial genotyping of CYP2C9 and VKORC1 can allow for individualized dosing of warfarin among patients with gene polymorphisms, potentially reducing the risk of stroke or bleeding.

Some Characteristics of One Type of High Reliability Organization.

ERIC Educational Resources Information Center

Roberts, Karlene H.

1990-01-01

Attempts to define organizational processes necessary to operate safely technologically complex organizations. Identifies nuclear powered aircraft carriers as examples of potentially hazardous organizations with histories of excellent operations. Discusses how carriers deal with components of risk and antecedents to catastrophe cited by Perrow and…

47 CFR 90.207 - Types of emissions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... under this part, see § 2.201 of this chapter. (1) The first symbol indicates the type of modulation on the transmitter carrier. A—Amplitude modulation, double sideband with identical information on each sideband. F—Frequency modulation. G—Phase modulation. J—Single sideband with suppressed carrier. P...

Generation of narrowband, high-intensity, carrier-envelope phase-stable pulses tunable between 4 and 18  THz.

PubMed

Liu, B; Bromberger, H; Cartella, A; Gebert, T; Först, M; Cavalleri, A

2017-01-01

We report on the generation of high-energy (1.9 μJ) far-infrared pulses tunable between 4 and 18 THz frequency. Emphasis is placed on tunability and on minimizing the bandwidth of these pulses to less than 1 THz, as achieved by difference-frequency mixing of two linearly chirped near-infrared pulses in the organic nonlinear crystal DSTMS. As the two near-infrared pulses are derived from amplification of the same white light continuum, their carrier envelope phase fluctuations are mutually correlated, and hence the difference-frequency THz field exhibits absolute phase stability. This source opens up new possibilities for the control of condensed matter and chemical systems by selective excitation of low-energy modes in a frequency range that has, to date, been difficult to access.

Kilohertz and Low-Frequency Electrical Stimulation With the Same Pulse Duration Have Similar Efficiency for Inducing Isometric Knee Extension Torque and Discomfort.

PubMed

Medeiros, Flávia Vanessa; Bottaro, Martim; Vieira, Amilton; Lucas, Tiago Pires; Modesto, Karenina Arrais; Bo, Antonio Padilha L; Cipriano, Gerson; Babault, Nicolas; Durigan, João Luiz Quagliotti

2017-06-01

To test the hypotheses that, as compared with pulsed current with the same pulse duration, kilohertz frequency alternating current would not differ in terms of evoked-torque production and perceived discomfort, and as a result, it would show the same current efficiency. A repeated-measures design with 4 stimuli presented in random order was used to test 25 women: (1) 500-microsecond pulse duration, (2) 250-microsecond pulse duration, (3) 500-microsecond pulse duration and low carrier frequency (1 kHz), (4) 250-microsecond pulse duration and high carrier frequency (4 kHz). Isometric peak torque of quadriceps muscle was measured using an isokinetic dynamometer. Discomfort was measured using a visual analog scale. Currents with long pulse durations induced approximately 21% higher evoked torque than short pulse durations. In addition, currents with 500 microseconds delivered greater amounts of charge than stimulation patterns using 250-microsecond pulse durations (P < 0.05). All currents presented similar discomfort. There was no difference on stimulation efficiency with the same pulse duration. Both kilohertz frequency alternating current and pulsed current, with the same pulse duration, have similar efficiency for inducing isometric knee extension torque and discomfort. However, neuromuscular electrical stimulation (NMES) with longer pulse duration induces higher NMES-evoked torque, regardless of the carrier frequency. Pulse duration is an important variable that should receive more attention for an optimal application of NMES in clinical settings.

47 CFR 51.319 - Specific unbundling requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Triennial Review Order, the high frequency portion of a copper loop shall no longer be required to be... the requesting telecommunications carrier using the high frequency portion of the loop. The high... the demarcation point at the end-user customer premises, and includes the high frequency portion of...

47 CFR 51.319 - Specific unbundling requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Triennial Review Order, the high frequency portion of a copper loop shall no longer be required to be... the requesting telecommunications carrier using the high frequency portion of the loop. The high... the demarcation point at the end-user customer premises, and includes the high frequency portion of...

47 CFR 51.319 - Specific unbundling requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Triennial Review Order, the high frequency portion of a copper loop shall no longer be required to be... the requesting telecommunications carrier using the high frequency portion of the loop. The high... the demarcation point at the end-user customer premises, and includes the high frequency portion of...

47 CFR 2.1515 - Spectral measurements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... applicable, change the type of modulation of the EPIRB and record the shift in carrier frequency as observed... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL... radiated signal from the EPIRB. A signal generator and frequency counter capable of operating at 121.5 and...

47 CFR 74.401 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... controlled carrier) during one radio frequency cycle under conditions of no modulation. Mean power. The power... long compared with the period of the lowest frequency encountered in the modulation. A time of 1/10... bandwidth. Occupied bandwidth. The frequency bandwidth such that, below its lower and above its upper...

Remote beating of parallel or orthogonally polarized dual-wavelength optical carriers for 5G millimeter-wave radio-over-fiber link.

PubMed

Wang, Huai-Yung; Chi, Yu-Chieh; Lin, Gong-Ru

2016-08-08

A novel millimeter-wave radio over fiber (MMW-RoF) link at carrier frequency of 35-GHz is proposed with the use of remotely beating MMW generation from reference master and injected slave colorless laser diode (LD) carriers at orthogonally polarized dual-wavelength injection-locking. The slave colorless LD supports lasing one of the dual-wavelength master modes with orthogonal polarizations, which facilitates the single-mode direct modulation of the quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) data. Such an injected single-carrier encoding and coupled dual-carrier transmission with orthogonal polarization effectively suppresses the cross-heterodyne mode-beating intensity noise, the nonlinear modulation (NLM) and four-wave mixing (FWM) sidemodes during injection locking and fiber transmission. In 25-km single-mode fiber (SMF) based wireline system, the dual-carrier under single-mode encoding provides baseband 24-Gbit/s 64-QAM OFDM transmission with an error vector magnitude (EVM) of 8.8%, a bit error rate (BER) of 3.7 × 10^-3, a power penalty of <1.5 dB. After remotely self-beating for wireless transmission, the beat MMW carrier at 35 GHz can deliver the passband 16-QAM OFDM at 4 Gbit/s to show corresponding EVM and BER of 15.5% and 1.4 × 10^-3, respectively, after 25-km SMF and 1.6-m free-space transmission.

Lexical frequency and acoustic reduction in spoken Dutch

NASA Astrophysics Data System (ADS)

Pluymaekers, Mark; Ernestus, Mirjam; Baayen, R. Harald

2005-10-01

This study investigates the effects of lexical frequency on the durational reduction of morphologically complex words in spoken Dutch. The hypothesis that high-frequency words are more reduced than low-frequency words was tested by comparing the durations of affixes occurring in different carrier words. Four Dutch affixes were investigated, each occurring in a large number of words with different frequencies. The materials came from a large database of face-to-face conversations. For each word containing a target affix, one token was randomly selected for acoustic analysis. Measurements were made of the duration of the affix as a whole and the durations of the individual segments in the affix. For three of the four affixes, a higher frequency of the carrier word led to shorter realizations of the affix as a whole, individual segments in the affix, or both. Other relevant factors were the sex and age of the speaker, segmental context, and speech rate. To accommodate for these findings, models of speech production should allow word frequency to affect the acoustic realizations of lower-level units, such as individual speech sounds occurring in affixes.

Materials experiment carrier concepts definition study. Volume 2: Technical report, part 2

NASA Technical Reports Server (NTRS)

1981-01-01

A materials experiment carrier (MEC) that provides effective accommodation of the given baseline materials processing in space (MPS) payloads and demonstration of the MPS platform concept for high priority materials processing science, multidiscipline MPS investigations, host carrier for commercial MPS payloads, and system economy of orbital operations is defined. The study flow of task work is shown. Study tasks featured analysis and trades to identify the MEC system concept options.

Transport limited interfacial carrier relaxation in a double-layer device investigated by time-resolved second harmonic generation and impedance spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, Le; Taguchi, Dai; Li, Jun; Manaka, Takaaki; Iwamoto, Mitsumasa

2011-02-01

The interfacial carrier relaxation in an indium tin oxide/polyimide/pentacene/Au double-layer device was studied in both time and frequency domains by using time-resolved second harmonic generation (TR-SHG) and impedance spectroscopy (IS), respectively. Although both hole and electron injection into the pentacene layer and their accumulation at the pentacene/polyimide interface were revealed in TR-SHG, it was only observed in IS under the hole injection condition. The "contradiction" between the two methods for the same carrier relaxation process was explained on the basis of a model, transport limited interfacial carrier relaxation, in which the quasistatic state governs the one-directional carrier transport.

Carrier-phase time transfer.

PubMed

Larson, K M; Levine, J

1999-01-01

We have conducted several time-transfer experiments using the phase of the GPS carrier rather than the code, as is done in current GPS-based time-transfer systems. Atomic clocks were connected to geodetic GPS receivers; we then used the GPS carrier-phase observations to estimate relative clock behavior at 6-minute intervals. GPS carrier-phase time transfer is more than an order of magnitude more precise than GPS common view time transfer and agrees, within the experimental uncertainty, with two-way satellite time-transfer measurements for a 2400 km baseline. GPS carrier-phase time transfer has a stability of 100 ps, which translates into a frequency uncertainty of about two parts in 10(-15) for an average time of 1 day.

76 FR 23109 - Enhancing Airline Passenger Protections

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-25

... Department; expanding the group of carriers that are required to adopt, follow, and audit customer service... carriers to those required to include their contingency plans and customer service plans on their websites..., and audit customer service plans. The rule also defined chronically delayed flights and deemed them to...

14 CFR 257.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... this part: (a) Air transportation means foreign air transportation or interstate air transportation as defined in 49 U.S.C. 40102 (a)(23) and (25) respectively. (b) Carrier means any air carrier or foreign air... scheduled passenger air transportation, including by wet lease. (c) Code-sharing arrangement means an...

Experimental evidence of zone-center optical phonon softening by accumulating holes in thin Ge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kabuyanagi, Shoichi; Nishimura, Tomonori; Yajima, Takeaki

2016-01-15

We discuss the impact of free carriers on the zone-center optical phonon frequency in germanium (Ge). By taking advantage of the Ge-on-insulator structure, we measured the Raman spectroscopy by applying back-gate bias. Phonon softening by accumulating holes in Ge film was clearly observed. This fact strongly suggests that the phonon softening in heavily-doped Ge is mainly attributed to the free carrier effect rather than the dopant atom counterpart. Furthermore, we propose that the free carrier effect on phonon softening is simply understandable from the viewpoint of covalent bonding modification by free carriers.

Frequency of a FAS ligand gene variant associated with inherited feline autoimmune lymphoproliferative syndrome in British shorthair cats in New Zealand.

PubMed

Aberdein, D; Munday, J S; Dittmer, K E; Heathcott, R W; Lyons, L A

2017-11-01

AIMS To determine the frequency of the FAS-ligand gene (FASLG) variant associated with feline autoimmune lymphoproliferative syndrome (FALPS) and the proportion of carriers of the variant in three British shorthair (BSH) breeding catteries in New Zealand. METHODS Buccal swabs were collected from all cats in two BSH breeding catteries from the South Island and one from the North Island of New Zealand. DNA was extracted and was tested for the presence of the FASLG variant using PCR. Cats with the FASLG variant were identified and the frequency of the FASLG variant allele calculated. Pedigree analysis was performed and inbreeding coefficients were calculated for cats with the FASLG variant. RESULTS Of 32 BSH cats successfully tested for the presence of the FASLG variant, one kitten (3%) was homozygous (FALPS-affected), and seven (22%) cats were heterozygous (carriers) for the FASLG variant allele, and 24 (75%) cats were homozygous for the wild type allele. The overall frequency of the FASLG variant allele in these 32 cats was 0.14. Cats carrying the FASLG variant were from all three breeding catteries sampled, including two catteries that had not previously reported cases of FALPS. Pedigree analysis revealed common ancestry of FALPS-affected and carrier cats within six generations, as well as frequent inbreeding, with inbreeding coefficients >0.12 for five cats with the FASLG variant. CONCLUSIONS AND CLINICAL RELEVANCE There was a high frequency of the FASLG variant allele (0.14) in this small sample of BSH cats, with 22% of healthy cats identified as carriers of the FASLG variant. For an inherited disease, lethal at a young age, in a small population in which inbreeding is common, these results are significant. To prevent future cases of disease and stop further spread of the FASLG variant allele within the BSH population in New Zealand, it is recommended that all BSH and BSH-cross cats be tested for the presence of the FASLG variant before mating. Cats identified as carriers of the variant allele should be desexed and not used for breeding. Results support the need for further investigations of the true frequency of the FASLG variant allele and occurrence of FALPS in the wider population of BSH cats in New Zealand.

47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25... frequencies and emission designators of such communications, and the frequencies and emission designators used... repeaters will communicate, the frequencies and emission designators of such communications, and the...

47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25... of such communications, and the frequencies and emission designators used by the repeaters to re..., the frequencies and emission designators of such communications, and the frequencies and emission...

47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25... frequencies and emission designators of such communications, and the frequencies and emission designators used... repeaters will communicate, the frequencies and emission designators of such communications, and the...

47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25... frequencies and emission designators of such communications, and the frequencies and emission designators used... repeaters will communicate, the frequencies and emission designators of such communications, and the...

47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25... frequencies and emission designators of such communications, and the frequencies and emission designators used... repeaters will communicate, the frequencies and emission designators of such communications, and the...

Time and Frequency Activities at the U.S. Naval Observatory

DTIC Science & Technology

2005-01-01

Naval Observatory, Washington, D.C.), pp. 325-332. [15] D. Kirchner, 1999, “Two Way Satellite Time and Frequency Transfer ( TWSTFT ),” Review of...of Carrier- Phase-Based Two-Way Satellite Time and Frequency Transfer ( TWSTFT ),” in Proceedings of the 36th Annual Precise Time and Time Interval

47 CFR 74.761 - Frequency tolerance.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.761 Frequency tolerance. The licensee of a low power TV, TV translator, or TV... channel carrier frequency if the low power TV, TV translator, or TV booster station is authorized with a...

An automatic frequency control loop using overlapping DFTs (Discrete Fourier Transforms)

NASA Technical Reports Server (NTRS)

Aguirre, S.

1988-01-01

An automatic frequency control (AFC) loop is introduced and analyzed in detail. The new scheme is a generalization of the well known Cross Product AFC loop that uses running overlapping discrete Fourier transforms (DFTs) to create a discriminator curve. Linear analysis is included and supported with computer simulations. The algorithm is tested in a low carrier to noise ratio (CNR) dynamic environment, and the probability of loss of lock is estimated via computer simulations. The algorithm discussed is a suboptimum tracking scheme with a larger frequency error variance compared to an optimum strategy, but offers simplicity of implementation and a very low operating threshold CNR. This technique can be applied during the carrier acquisition and re-acquisition process in the Advanced Receiver.

Efficient carrier-envelope offset frequency stabilization through gain modulation via stimulated emission.

PubMed

Karlen, Lauriane; Buchs, Gilles; Portuondo-Campa, Erwin; Lecomte, Steve

2016-01-15

A novel scheme for intracavity control of the carrier-envelope offset (CEO) frequency of a 100 MHz mode-locked Er:Yb:glass diode-pumped solid-state laser (DPSSL) based on the modulation of the laser gain via stimulated emission of the excited Er(3+) ions is demonstrated. This method allows us to bypass the ytterbium system few-kHz low-pass filter in the f(CEO) stabilization loop and thus to push the phase lock bandwidth up to a limit close to the relaxation oscillations frequency of the erbium system. A phase lock bandwidth above 70 kHz has been achieved with the fully stabilized laser, leading to an integrated phase noise [1 Hz-1 MHz] of 120 mrad.

A straightforward frequency-estimation technique for GPS carrier-phase time transfer.

PubMed

Hackman, Christine; Levine, Judah; Parker, Thomas E; Piester, Dirk; Becker, Jürgen

2006-09-01

Although Global Positioning System (GPS) carrier-phase time transfer (GPSCPTT) offers frequency stability approaching 10-15 at averaging times of 1 d, a discontinuity occurs in the time-transfer estimates between the end of one processing batch (1-3 d in length) and the beginning of the next. The average frequency over a multiday analysis period often has been computed by first estimating and removing these discontinuities, i.e., through concatenation. We present a new frequency-estimation technique in which frequencies are computed from the individual batches then averaged to obtain the mean frequency for a multiday period. This allows the frequency to be computed without the uncertainty associated with the removal of the discontinuities and requires fewer computational resources. The new technique was tested by comparing the fractional frequency-difference values it yields to those obtained using a GPSCPTT concatenation method and those obtained using two-way satellite time-and-frequency transfer (TWSTFT). The clocks studied were located in Braunschweig, Germany, and in Boulder, CO. The frequencies obtained from the GPSCPTT measurements using either method agreed with those obtained from TWSTFT at several parts in 1016. The frequency values obtained from the GPSCPTT data by use of the new method agreed with those obtained using the concatenation technique at 1-4 x 10(-16).

Photo-conductive detection of continuous THz waves via manipulated ultrafast process in nanostructures

NASA Astrophysics Data System (ADS)

Moon, Kiwon; Lee, Eui Su; Lee, Il-Min; Park, Dong Woo; Park, Kyung Hyun

2018-01-01

Time-domain and frequency-domain terahertz (THz) spectroscopy systems often use materials fabricated with exotic and expensive methods that intentionally introduce defects to meet short carrier lifetime requirements. In this study, we demonstrate the development of a nano-photomixer that meets response speed requirements without using defect-incorporated, low-temperature-grown (LTG) semiconductors. Instead, we utilized a thin InGaAs layer grown on a semi-insulating InP substrate by metal-organic chemical vapor deposition (MOCVD) combined with nano-electrodes to manipulate local ultrafast photo-carrier dynamics via a carefully designed field-enhancement and plasmon effect. The developed nano-structured photomixer can detect continuous-wave THz radiation up to a frequency of 2 THz with a peak carrier collection efficiency of 5%, which is approximately 10 times better than the reference efficiency of 0.4%. The better efficiency results from the high carrier mobility of the MOCVD-grown InGaAs thin layer with the coincidence of near-field and plasmon-field distributions in the nano-structure. Our result not only provides a generally applicable methodology for manipulating ultrafast carrier dynamics by means of nano-photonic techniques to break the trade-off relation between the carrier lifetime and mobility in typical LTG semiconductors but also contributes to mass-producible photo-conductive THz detectors to facilitate the widespread application of THz technology.

The dependence of graphene Raman D-band on carrier density.

PubMed

Liu, Junku; Li, Qunqing; Zou, Yuan; Qian, Qingkai; Jin, Yuanhao; Li, Guanhong; Jiang, Kaili; Fan, Shoushan

2013-01-01

Raman spectroscopy has been an integral part of graphene research and can provide information about graphene structure, electronic characteristics, and electron-phonon interactions. In this study, the characteristics of the graphene Raman D-band, which vary with carrier density, are studied in detail, including the frequency, full width half-maximum, and intensity. We find the Raman D-band frequency increases for hole doping and decreases for electron doping. The Raman D-band intensity increases when the Fermi level approaches half of the excitation energy and is higher in the case of electron doping than that of hole doping. These variations can be explained by electron-phonon interaction theory and quantum interference between different Raman pathways in graphene. The intensity ratio of Raman D- and G-band, which is important for defects characterization in graphene, shows a strong dependence on carrier density.

High-amplitude VLF transmitter signals and associated sidebands observed near the magnetic equatorial plane on the ISEE 1 satellite

NASA Technical Reports Server (NTRS)

Bell, T. F.

1985-01-01

New high-altitude ISEE 1 satellite observations of high-amplitude nonducted signals from the Omega navigation transmitter in North Dakota are reported. The amplitude of the signal was approximately 16-26 dB higher than that of similar signals observed at comparable locations on other days. Over the range L = 3.3-3.7, the transmitter pulses at 13.1 and 13.6 kHz were associated with sideband signals spaced in frequency roughly symmetrically about the carrier and generally reduced in amplitude by about 5 dB with respect to the carrier. The strongest sidebands were generally offset in frequency from the carrier by about + or - 55 Hz. Reasons are discussed for believing that the unusually high amplitude of the signals was due to wave amplification through the whistler-mode instability.

A new unequal-weighted triple-frequency first order ionosphere correction algorithm and its application in COMPASS

NASA Astrophysics Data System (ADS)

Liu, WenXiang; Mou, WeiHua; Wang, FeiXue

2012-03-01

As the introduction of triple-frequency signals in GNSS, the multi-frequency ionosphere correction technology has been fast developing. References indicate that the triple-frequency second order ionosphere correction is worse than the dual-frequency first order ionosphere correction because of the larger noise amplification factor. On the assumption that the variances of three frequency pseudoranges were equal, other references presented the triple-frequency first order ionosphere correction, which proved worse or better than the dual-frequency first order correction in different situations. In practice, the PN code rate, carrier-to-noise ratio, parameters of DLL and multipath effect of each frequency are not the same, so three frequency pseudorange variances are unequal. Under this consideration, a new unequal-weighted triple-frequency first order ionosphere correction algorithm, which minimizes the variance of the pseudorange ionosphere-free combination, is proposed in this paper. It is found that conventional dual-frequency first-order correction algorithms and the equal-weighted triple-frequency first order correction algorithm are special cases of the new algorithm. A new pseudorange variance estimation method based on the three carrier combination is also introduced. Theoretical analysis shows that the new algorithm is optimal. The experiment with COMPASS G3 satellite observations demonstrates that the ionosphere-free pseudorange combination variance of the new algorithm is smaller than traditional multi-frequency correction algorithms.

Exciton recombination dynamics in CdSe nanowires: bimolecular to three-carrier Auger kinetics.

PubMed

Robel, István; Bunker, Bruce A; Kamat, Prashant V; Kuno, Masaru

2006-07-01

Ultrafast relaxation dynamics of charge carriers in CdSe quantum wires with diameters between 6 and 8 nm are studied as a function of carrier density. At high electron-hole pair densities above 10(19) cm(-3) the dominant process for carrier cooling is the "bimolecular" Auger recombination of one-dimensional (1D) excitons. However, below this excitation level an unexpected transition from a bimolecular (exciton-exciton) to a three-carrier Auger relaxation mechanism occurs. Thus, depending on excitation intensity, electron-hole pair relaxation dynamics in the nanowires exhibit either 1D or 0D (quantum dot) character. This dual nature of the recovery kinetics defines an optimal intensity for achieving optical gain in solution-grown nanowires given the different carrier-density-dependent scaling of relaxation rates in either regime.

Stable optical frequency comb generation and applications in arbitrary waveform generation, signal processing and optical data mining

NASA Astrophysics Data System (ADS)

Ozharar, Sarper

This thesis focuses on the generation and applications of stable optical frequency combs. Optical frequency combs are defined as equally spaced optical frequencies with a fixed phase relation among themselves. The conventional source of optical frequency combs is the optical spectrum of the modelocked lasers. In this work, we investigated alternative methods for optical comb generation, such as dual sine wave phase modulation, which is more practical and cost effective compared to modelocked lasers stabilized to a reference. Incorporating these comblines, we have generated tunable RF tones using the serrodyne technique. The tuning range was +/-1 MHz, limited by the electronic waveform generator, and the RF carrier frequency is limited by the bandwidth of the photodetector. Similarly, using parabolic phase modulation together with time division multiplexing, RF chirp extension has been realized. Another application of the optical frequency combs studied in this thesis is real time data mining in a bit stream. A novel optoelectronic logic gate has been developed for this application and used to detect an 8 bit long target pattern. Also another approach based on orthogonal Hadamard codes have been proposed and explained in detail. Also novel intracavity modulation schemes have been investigated and applied for various applications such as (a) improving rational harmonic modelocking for repetition rate multiplication and pulse to pulse amplitude equalization, (b) frequency skewed pulse generation for ranging and (c) intracavity active phase modulation in amplitude modulated modelocked lasers for supermode noise spur suppression and integrated jitter reduction. The thesis concludes with comments on the future work and next steps to improve some of the results presented in this work.

Ultra wideband surface wave communications

NASA Astrophysics Data System (ADS)

Lacomb, Julie Anne

Ultra Wideband (UWB), an impulse carrier waveform, was applied at HF-VHF frequencies to utilize surface wave propagation. UWB involves the propagation of transient pulses rather than continuous waves which makes the system easier to implement, inexpensive, low power and small. Commercial UWB for wireless personal area networks is 3.1 to 10.6 GHz band as approved by the FCC with ranges up to 12 ft. The use of surface wave propagation (instead of commercial SHF UWB) extends the communication range. Surface wave is a means of propagation where the wave is guided by the surface of the Earth. Surface wave is efficient at low frequencies, VLF to HF. The UWB HF channel was modeled and also experimentally characterized. The Federal Communications Commission (FCC) defines UWB as a signal with either a fractional bandwidth of 20% of the center frequency or a bandwidth of 500MHz. Designing an antenna to operate over the 20% bandwidth requirement of UWB is one of the greatest challenges. Two different antenna designs are presented, a spoke top antenna and a traveling wave antenna with photonic bandgap. These designs were implemented at the commercial UWB frequencies (3.1--10.6 GHz) due to availability of modeling tools for the higher frequencies, the reduced antenna size and the availability of measurement facilities. The spoke top was optimum for replication of the time domain input signal. The traveling wave antenna with photonic bandgap demonstrated increased impedance bandwidth of the antenna.

Dry powder aerosols generated by standardized entrainment tubes from alternative sugar blends: 3. Trehalose dihydrate and D-mannitol carriers.

PubMed

Mansour, Heidi M; Xu, Zhen; Hickey, Anthony J

2010-08-01

The relationship between physicochemical properties of drug/carrier blends and aerosol drug powder delivery was evaluated. Four pulmonary drugs each representing the major pulmonary therapeutic classes and with a different pharmacological action were employed. Specifically, the four pulmonary drugs were albuterol sulfate, ipratropium bromide monohydrate, disodium cromoglycate, and fluticasone propionate. The two carrier sugars, each representing a different sugar class, were D-mannitol and trehalose dihydrate. Dry powder aerosols (2%, w/w, drug in carrier) delivered using standardized entrainment tubes (SETs) were characterized by twin-stage liquid impinger. The fine particle fraction (FPF) was correlated with SET shear stress, tau(s), and the maximum fine particle fraction (FPF(max)) was correlated with a deaggregation constant, k(d), by using a powder aerosol deaggregation equation (PADE) by nonlinear and linear regression analyses applied to pharmaceutical inhalation aerosol systems in the solid state. For the four pulmonary drugs representing the major pulmonary therapeutic classes and two chemically distinct pulmonary sugar carriers (non-lactose types) aerosolized with SETs having well-defined shear stress values, excellent correlation and predictive relationships were demonstrated for the novel and rigorous application of PADE for dry powder inhalation aerosol dispersion within a well-defined shear stress range, in the context of pulmonary drug/sugar carrier physicochemical and interfacial properties. (c) 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Method and apparatus for pulse width modulation control of an AC induction motor

DOEpatents

Geppert, Steven; Slicker, James M.

1984-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Charge carrier dynamics in PMMA-LiClO4 based polymer electrolytes plasticized with different plasticizers

NASA Astrophysics Data System (ADS)

Pal, P.; Ghosh, A.

2017-07-01

We have studied the charge carrier dynamics in poly(methylmethacrylate)-LiClO4 polymer electrolytes plasticized with different plasticizers such as ethylene carbonate (EC), propylene carbonate (PC), polyethylene glycol (PEG), and dimethyl carbonate (DMC). We have measured the broadband complex conductivity spectra of these electrolytes in the frequency range of 0.01 Hz-3 GHz and in the temperature range of 203 K-363 K and analyzed the conductivity spectra in the framework of the random barrier model by taking into account the contribution of the electrode polarization observed at low frequencies and/or at high temperatures. It is observed that the temperature dependences of the ionic conductivity and relaxation time follow the Vogel-Tammann-Fulcher relation for all plasticized electrolytes. We have also performed the scaling of the conductivity spectra, which indicates that the charge carrier dynamics is almost independent of temperature and plasticizers in a limited frequency range. The existence of nearly constant loss in these electrolytes has been observed at low temperatures and/or high frequencies. We have studied the dielectric relaxation in these electrolytes using electric modulus formalism and obtained the stretched exponent and the decay function. We have observed less cooperative ion dynamics in electrolytes plasticized with DMC compared to electrolytes plasticized with EC, PC, and PEG.

Simultaneous displacement and slope measurement in electronic speckle pattern interferometry using adjustable aperture multiplexing.

PubMed

Lu, Min; Wang, Shengjia; Aulbach, Laura; Koch, Alexander W

2016-08-01

This paper suggests the use of adjustable aperture multiplexing (AAM), a method which is able to introduce multiple tunable carrier frequencies into a three-beam electronic speckle pattern interferometer to measure the out-of-plane displacement and its first-order derivative simultaneously. In the optical arrangement, two single apertures are located in the object and reference light paths, respectively. In cooperation with two adjustable mirrors, virtual images of the single apertures construct three pairs of virtual double apertures with variable aperture opening sizes and aperture distances. By setting the aperture parameter properly, three tunable spatial carrier frequencies are produced within the speckle pattern and completely separate the information of three interferograms in the frequency domain. By applying the inverse Fourier transform to a selected spectrum, its corresponding phase difference distribution can thus be evaluated. Therefore, we can obtain the phase map due to the deformation as well as its slope of the test surface from two speckle patterns which are recorded at different loading events. By this means, simultaneous and dynamic measurements are realized. AAM has greatly simplified the measurement system, which contributes to improving the system stability and increasing the system flexibility and adaptability to various measurement requirements. This paper presents the AAM working principle, the phase retrieval using spatial carrier frequency, and preliminary experimental results.

Temporal modulation transfer functions in cochlear implantees using a method that limits overall loudness cues

PubMed Central

Fraser, Matthew; McKay, Colette M.

2012-01-01

Temporal modulation transfer functions (TMTFs) were measured for six users of cochlear implants, using different carrier rates and levels. Unlike most previous studies investigating modulation detection, the experimental design limited potential effects of overall loudness cues. Psychometric functions (percent correct discrimination of modulated from unmodulated stimuli versus modulation depth) were obtained. For each modulation depth, each modulated stimulus was loudness balanced to the unmodulated reference stimulus, and level jitter was applied in the discrimination task. The loudness-balance data showed that the modulated stimuli were louder than the unmodulated reference stimuli with the same average current, thus confirming the need to limit loudness cues when measuring modulation detection. TMTFs measured in this way had a low-pass characteristic, with a cut-off frequency (at comfortably loud levels) similar to that for normal-hearing listeners. A reduction in level caused degradation in modulation detection efficiency and a lower-cut-off frequency (i.e. poorer temporal resolution). An increase in carrier rate also led to a degradation in modulation detection efficiency, but only at lower levels or higher modulation frequencies. When detection thresholds were expressed as a proportion of dynamic range, there was no effect of carrier rate for the lowest modulation frequency (50 Hz) at either level. PMID:22146425

Method and apparatus for pulse width modulation control of an AC induction motor

NASA Technical Reports Server (NTRS)

Geppert, Steven (Inventor); Slicker, James M. (Inventor)

1984-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

PREVALENCE OF COMBINATORIAL CYP2C9 AND VKORC1 GENOTYPES IN PUERTO RICANS: IMPLICATIONS FOR WARFARIN MANAGEMENT IN HISPANICS

PubMed Central

Duconge, Jorge; Cadilla, Carmen L.; Windemuth, Andreas; Kocherla, Mohan; Gorowski, Krystyna; Seip, Richard L.; Bogaard, Kali; Renta, Jessica Y.; Piovanetti, Paola; D’Agostino, Darrin; Santiago-Borrero, Pedro J.; Ruaño, Gualberto

2010-01-01

Polymorphisms in the cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) genes significantly alter the effective warfarin dose. We determined the frequencies of alleles, single carriers, and double carriers of single nucleotide polymorphisms (SNPs) in the CYP2C9 and VKORC1 genes in a Puerto Rican cohort and gauged the impact of these polymorphisms on warfarin dosage using a published algorithm. A total of 92 DNA samples were genotyped using Luminex® x-MAP technology. The polymorphism frequencies were 6.52%, 5.43% and 28.8% for CYP2C9 *2, *3 and VKORC1-1639 G>A polymorphisms, respectively. The prevalence of combinatorial genotypes was 16% for carriers of both the CYP2C9 and VKORC1 polymorphisms, 9% for carriers of CYP2C9 polymorphisms, 35% for carriers of the VKORC1 polymorphism, and the remaining 40% were non-carriers for either gene. Based on a published warfarin dosing algorithm, single, double and triple carriers of functionally deficient polymorphisms predict reductions of 1.0–1.6, 2.0–2.9, and 2.9–3.7 mg/day, respectively, in warfarin dose. Overall, 60% of the population carried at least a single polymorphism predicting deficient warfarin metabolism or responsiveness and 13% were double carriers with polymorphisms in both genes studied. Combinatorial genotyping of CYP2C9 and VKORC1 can allow for individualized dosing of warfarin among patients with gene polymorphisms, potentially reducing the risk of stroke or bleeding. PMID:20073138

Real-Time Point Positioning Performance Evaluation of Single-Frequency Receivers Using NASA's Global Differential GPS System

NASA Technical Reports Server (NTRS)

Muellerschoen, Ronald J.; Iijima, Byron; Meyer, Robert; Bar-Sever, Yoaz; Accad, Elie

2004-01-01

This paper evaluates the performance of a single-frequency receiver using the 1-Hz differential corrections as provided by NASA's global differential GPS system. While the dual-frequency user has the ability to eliminate the ionosphere error by taking a linear combination of observables, the single-frequency user must remove or calibrate this error by other means. To remove the ionosphere error we take advantage of the fact that the magnitude of the group delay in range observable and the carrier phase advance have the same magnitude but are opposite in sign. A way to calibrate this error is to use a real-time database of grid points computed by JPL's RTI (Real-Time Ionosphere) software. In both cases we evaluate the positional accuracy of a kinematic carrier phase based point positioning method on a global extent.

Application of Excitation from Multiple Locations on a Simplified High-Lift System

NASA Technical Reports Server (NTRS)

Melton, LaTunia Pack; Yao, Chung-Sheng; Seifert, Avi

2004-01-01

A series of active flow control experiments were recently conducted on a simplified high-lift system. The purpose of the experiments was to explore the prospects of eliminating all but simply hinged leading and trailing edge flaps, while controlling separation on the supercritical airfoil using multiple periodic excitation slots. Excitation was provided by three. independently controlled, self-contained, piezoelectric actuators. Low frequency excitation was generated through amplitude modulation of the high frequency carrier wave, the actuators' resonant frequencies. It was demonstrated, for the first time, that pulsed modulated signal from two neighboring slots interact favorably to increase lift. Phase sensitivity at the low frequency was measured, even though the excitation was synthesized from the high-frequency carrier wave. The measurements were performed at low Reynolds numbers and included mean and unsteady surface pressures, surface hot-films, wake pressures and particle image velocimetry. A modest (6%) increase in maximum lift (compared to the optimal baseline) was obtained due t o the activation of two of the three actuators.

Electrical and optical characterizations of InAs/GaAs quantum dot solar cells

NASA Astrophysics Data System (ADS)

Han, Im Sik; Kim, Seung Hyun; Kim, Jong Su; Noh, Sam Kyu; Lee, Sang Jun; Kim, Honggyun; Kim, Deok-Kee; Leem, Jae-Young

2018-03-01

The electrical and optical characterizations of InAs/GaAs quantum dot solar cells (QDSCs) were investigated by frequency dependent capacitance-voltage ( C- V) measurements and photoreflectance (PR) spectroscopy. The C- V results confirmed that the frequency dependent junction capacitance ( C j) of QDSC is sensitive to the carrier exhaustion process through trapping and recapturing in the strain-induced defects and QD states caused by the interface strain between InAs and GaAs materials. As a result, at a low frequency (≤ 200 kHz), the C j of the QDSCs decreased with increasing InAs deposition thickness ( θ), leading to the decrease in carrier concentration ( N d) of the n-GaAs absorber layer due to the carrier losses processes caused by the trapping and re-capturing in the defects and the relatively large QDs. At θ ≤ 2.0 ML, the p-n junction electric field strength ( F pn) of the QDSCs which was evaluated by PR spectra decreased with increasing excitation photon intensity ( I ex) due to the typical field screening effect in the SC structure. On the other hand, the F pn of QDSCs with θ ≥ 2.5 ML approached a constant value with a relatively high I ex, which suggests that the decrease in photo-generated carriers in the QDSC was caused by the re-capturing and trapping process.

How to Tackle the Challenge of siRNA Delivery with Sequence-Defined Oligoamino Amides.

PubMed

Reinhard, Sören; Wagner, Ernst

2017-01-01

RNA interference (RNAi) as a mechanism of gene regulation provides exciting opportunities for medical applications. Synthetic small interfering RNA (siRNA) triggers the knockdown of complementary mRNA sequences in a catalytic fashion and has to be delivered into the cytosol of the targeted cells. The design of adequate carrier systems to overcome multiple extracellular and intracellular roadblocks within the delivery process has utmost importance. Cationic polymers form polyplexes through electrostatic interaction with negatively charged nucleic acids and present a promising class of carriers. Issues of polycations regarding toxicity, heterogeneity, and polydispersity can be overcome by solid-phase-assisted synthesis of sequence-defined cationic oligomers. These medium-sized highly versatile nucleic acid carriers display low cytotoxicity and can be modified and tailored in multiple ways to meet specific requirements of nucleic acid binding, polyplex size, shielding, targeting, and intracellular release of the cargo. In this way, sequence-defined cationic oligomers can mimic the dynamic and bioresponsive behavior of viruses. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Off-axis illumination direct-to-digital holography

DOEpatents

Thomas, Clarence E.; Price, Jeffery R.; Voelkl, Edgar; Hanson, Gregory R.

2004-06-08

Systems and methods are described for off-axis illumination direct-to-digital holography. A method of recording an off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis, includes: reflecting a reference beam from a reference mirror at a non-normal angle; reflecting an object beam from an object at an angle with respect to an optical axis defined by a focusing lens; focusing the reference beam and the object beam at a focal plane of a digital recorder to form the off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; digitally recording the off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; Fourier analyzing the recorded off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes by transforming axes of the recorded off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes in Fourier space to sit on top of a heterodyne carrier frequency defined as an angle between the reference beam and the object beam; applying a digital filter to cut off signals around an original origin; and then performing an inverse Fourier transform.

Comparison of CDMA and FDMA for the MobileStar(sm) system

NASA Technical Reports Server (NTRS)

Jacobs, I. M.; Gilhousen, K. S.; Weaver, L. A.; Renshaw, K.; Murphy, T.

1988-01-01

Spread-spectrum code division multiple access (CDMA) and single channel per carrier frequency division multiple access (FDMA) systems are compared for spectrum efficiency. CDMA is shown to have greater maximum throughput than FDMA for the MobileStar(sm) system which uses digital voice activated carriers and directive circularly polarized satellite antennas.

Phase-locked Optical Signal Recovery

DTIC Science & Technology

2009-01-01

detection . However, implementing an optical phase lock loop ( OPLL ) to generate the synchronised carrier for the homodyne technique requires... Loop (OIPLL) in which a narrow bandwidth optical phase lock loop ( OPLL ) is used to control the free -running frequency of an optically injection...receiver uses an Optical Injection Phase Lock Loop (OIPLL) for carrier recovery,

Phase-locked Optical Signal Recovery

DTIC Science & Technology

2009-01-01

detection . However, implementing an optical phase lock loop ( OPLL ) to generate the synchronised carrier for the homodyne technique requires... Loop (OIPLL) in which a narrow bandwidth optical phase lock loop ( OPLL ) is used to control the free -running frequency of an optically injection...The receiver uses an Optical Injection Phase Lock Loop (OIPLL) for carrier

47 CFR Figure 4 to Subpart N of... - Example of EPIRB Carrier Component

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false Example of EPIRB Carrier Component 4 Figure 4 to Subpart N of Part 2 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY... Emergency Position Indicating Radiobeacons (EPIRBs) Pt. 2, Subpt. N, Fig. 4 Figure 4 to Subpart N of Part 2...

47 CFR Figure 4 to Subpart N of... - Example of EPIRB Carrier Component

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Example of EPIRB Carrier Component 4 Figure 4 to Subpart N of Part 2 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY... Emergency Position Indicating Radiobeacons (EPIRBs) Pt. 2, Subpt. N, Fig. 4 Figure 4 to Subpart N of Part 2...

Demodulator for carrier transducers

NASA Technical Reports Server (NTRS)

Roller, R. F. (Inventor)

1974-01-01

A carrier type transducer is supplied with a carrier wave via an audio amplifier, a filter, a frequency divider, and an oscillator. The carrier is modulated in accordance with the parameter being measured by the transducer and is fed to the input of a digital data system which may include a voltmeter. The output of the oscillator and the output of each stage of the divider are fed to an AND or a NAND gate and suitable variable and fixed delay circuits to the command input of the digital data system. With this arrangement, the digital data system is commanded to sample at the proper time so that the average voltage of the modulated carrier is measured. It may be utilized with ancillary circuitry for control of the parameter

47 CFR 74.762 - Frequency measurements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Booster Stations § 74.762 Frequency measurements. (a) The licensee of a low power TV station, a TV translator, or a TV booster station must measure the carrier frequencies of its output channel as often as... intervals not exceeding 14 months. (b) In the event that a low power TV, TV translator, or TV booster...

47 CFR 74.762 - Frequency measurements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Booster Stations § 74.762 Frequency measurements. (a) The licensee of a low power TV station, a TV translator, or a TV booster station must measure the carrier frequencies of its output channel as often as... intervals not exceeding 14 months. (b) In the event that a low power TV, TV translator, or TV booster...

47 CFR 74.762 - Frequency measurements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Booster Stations § 74.762 Frequency measurements. (a) The licensee of a low power TV station, a TV translator, or a TV booster station must measure the carrier frequencies of its output channel as often as... intervals not exceeding 14 months. (b) In the event that a low power TV, TV translator, or TV booster...

47 CFR 74.762 - Frequency measurements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Booster Stations § 74.762 Frequency measurements. (a) The licensee of a low power TV station, a TV translator, or a TV booster station must measure the carrier frequencies of its output channel as often as... intervals not exceeding 14 months. (b) In the event that a low power TV, TV translator, or TV booster...

Advances in Time and Frequency Transfer From Dual-Frequency GPS Pseudorange and Carrier-Phase Observations

DTIC Science & Technology

2008-12-01

collocated independent time transfer techniques such as Two-Way Satellite Time and Frequency Transfer ( TWSTFT ) [10,11]. The issue of pseudorange errors...transfer methods, e.g. TWSTFT . There is a side benefit that far exceeds just meeting the objective we have set. The new model explicitly reveals, on

Time and Frequency Activities at the U.S. Naval Observatory

DTIC Science & Technology

2008-12-01

USA (Institute of Navigation, Alexandria, Virginia). [22] D. Kirchner, 1999, “Two Way Satellite Time and Frequency Transfer ( TWSTFT ),” Review of...Shäfer, and A. Pawlitzki, 2005, “Development of Carrier- Phase-Based Two-Way Satellite Time and Frequency Transfer ( TWSTFT ),” in Proceedings of the 36th

Time and Frequency Activities at the U.S. Naval Observatory

DTIC Science & Technology

2007-01-01

Time and Frequency Transfer ( TWSTFT ),” Review of Radio Science (Oxford Science Publications), pp. 27-44. 14 38th Annual Precise Time and Time Interval...Fonville, D. Matsakis, W. Shäfer, and A. Pawlitzki, 2005, “Development of Carrier- Phase-Based Two-Way Satellite Time and Frequency Transfer ( TWSTFT

Defining the Effect of the 16p11.2 Duplication on Cognition, Behavior, and Medical Comorbidities

PubMed Central

D’Angelo, Debra; Lebon, Sébastien; Chen, Qixuan; Martin-Brevet, Sandra; Snyder, LeeAnne Green; Hippolyte, Loyse; Hanson, Ellen; Maillard, Anne M.; Faucett, W. Andrew; Macé, Aurélien; Pain, Aurélie; Bernier, Raphael; Chawner, Samuel J. R. A.; David, Albert; Andrieux, Joris; Aylward, Elizabeth; Baujat, Genevieve; Caldeira, Ines; Conus, Philippe; Ferrari, Carrina; Forzano, Francesca; Gérard, Marion; Goin-Kochel, Robin P.; Grant, Ellen; Hunter, Jill V.; Isidor, Bertrand; Jacquette, Aurélia; Jønch, Aia E.; Keren, Boris; Lacombe, Didier; Caignec, Cédric Le; Martin, Christa Lese; Männik, Katrin; Metspalu, Andres; Mignot, Cyril; Mukherjee, Pratik; Owen, Michael J.; Passeggeri, Marzia; Rooryck-Thambo, Caroline; Rosenfeld, Jill A.; Spence, Sarah J.; Steinman, Kyle J.; Tjernagel, Jennifer; Van Haelst, Mieke; Shen, Yiping; Draganski, Bogdan; Sherr, Elliott H.; Ledbetter, David H.; van den Bree, Marianne B. M.; Beckmann, Jacques S.; Spiro, John E.; Reymond, Alexandre; Jacquemont, Sébastien; Chung, Wendy K.

2018-01-01

IMPORTANCE The 16p11.2 BP4-BP5 duplication is the copy number variant most frequently associated with autism spectrum disorder (ASD), schizophrenia, and comorbidities such as decreased body mass index (BMI). OBJECTIVES To characterize the effects of the 16p11.2 duplication on cognitive, behavioral, medical, and anthropometric traits and to understand the specificity of these effects by systematically comparing results in duplication carriers and reciprocal deletion carriers, who are also at risk for ASD. DESIGN, SETTING, AND PARTICIPANTS This international cohort study of 1006 study participants compared 270 duplication carriers with their 102 intrafamilial control individuals, 390 reciprocal deletion carriers, and 244 deletion controls from European and North American cohorts. Data were collected from August 1, 2010, to May 31, 2015 and analyzed from January 1 to August 14, 2015. Linear mixed models were used to estimate the effect of the duplication and deletion on clinical traits by comparison with noncarrier relatives. MAIN OUTCOMES AND MEASURES Findings on the Full-Scale IQ (FSIQ), Nonverbal IQ, and Verbal IQ; the presence of ASD or other DSM-IV diagnoses; BMI; head circumference; and medical data. RESULTS Among the 1006 study participants, the duplication was associated with a mean FSIQ score that was lower by 26.3 points between proband carriers and noncarrier relatives and a lower mean FSIQ score (16.2-11.4 points) in nonproband carriers. The mean overall effect of the deletion was similar (−22.1 points; P < .001). However, broad variation in FSIQ was found, with a 19.4- and 2.0-fold increase in the proportion of FSIQ scores that were very low (≤40) and higher than the mean (>100) compared with the deletion group (P < .001). Parental FSIQ predicted part of this variation (approximately 36.0% in hereditary probands). Although the frequency of ASD was similar in deletion and duplication proband carriers (16.0% and 20.0%, respectively), the FSIQ was significantly lower (by 26.3 points) in the duplication probands with ASD. There also were lower head circumference and BMI measurements among duplication carriers, which is consistent with the findings of previous studies. CONCLUSIONS AND RELEVANCE The mean effect of the duplication on cognition is similar to that of the reciprocal deletion, but the variance in the duplication is significantly higher, with severe and mild subgroups not observed with the deletion. These results suggest that additional genetic and familial factors contribute to this variability. Additional studies will be necessary to characterize the predictors of cognitive deficits. PMID:26629640

Defining the Effect of the 16p11.2 Duplication on Cognition, Behavior, and Medical Comorbidities.

PubMed

D'Angelo, Debra; Lebon, Sébastien; Chen, Qixuan; Martin-Brevet, Sandra; Snyder, LeeAnne Green; Hippolyte, Loyse; Hanson, Ellen; Maillard, Anne M; Faucett, W Andrew; Macé, Aurélien; Pain, Aurélie; Bernier, Raphael; Chawner, Samuel J R A; David, Albert; Andrieux, Joris; Aylward, Elizabeth; Baujat, Genevieve; Caldeira, Ines; Conus, Philippe; Ferrari, Carrina; Forzano, Francesca; Gérard, Marion; Goin-Kochel, Robin P; Grant, Ellen; Hunter, Jill V; Isidor, Bertrand; Jacquette, Aurélia; Jønch, Aia E; Keren, Boris; Lacombe, Didier; Le Caignec, Cédric; Martin, Christa Lese; Männik, Katrin; Metspalu, Andres; Mignot, Cyril; Mukherjee, Pratik; Owen, Michael J; Passeggeri, Marzia; Rooryck-Thambo, Caroline; Rosenfeld, Jill A; Spence, Sarah J; Steinman, Kyle J; Tjernagel, Jennifer; Van Haelst, Mieke; Shen, Yiping; Draganski, Bogdan; Sherr, Elliott H; Ledbetter, David H; van den Bree, Marianne B M; Beckmann, Jacques S; Spiro, John E; Reymond, Alexandre; Jacquemont, Sébastien; Chung, Wendy K

2016-01-01

The 16p11.2 BP4-BP5 duplication is the copy number variant most frequently associated with autism spectrum disorder (ASD), schizophrenia, and comorbidities such as decreased body mass index (BMI). To characterize the effects of the 16p11.2 duplication on cognitive, behavioral, medical, and anthropometric traits and to understand the specificity of these effects by systematically comparing results in duplication carriers and reciprocal deletion carriers, who are also at risk for ASD. This international cohort study of 1006 study participants compared 270 duplication carriers with their 102 intrafamilial control individuals, 390 reciprocal deletion carriers, and 244 deletion controls from European and North American cohorts. Data were collected from August 1, 2010, to May 31, 2015 and analyzed from January 1 to August 14, 2015. Linear mixed models were used to estimate the effect of the duplication and deletion on clinical traits by comparison with noncarrier relatives. Findings on the Full-Scale IQ (FSIQ), Nonverbal IQ, and Verbal IQ; the presence of ASD or other DSM-IV diagnoses; BMI; head circumference; and medical data. Among the 1006 study participants, the duplication was associated with a mean FSIQ score that was lower by 26.3 points between proband carriers and noncarrier relatives and a lower mean FSIQ score (16.2-11.4 points) in nonproband carriers. The mean overall effect of the deletion was similar (-22.1 points; P < .001). However, broad variation in FSIQ was found, with a 19.4- and 2.0-fold increase in the proportion of FSIQ scores that were very low (≤40) and higher than the mean (>100) compared with the deletion group (P < .001). Parental FSIQ predicted part of this variation (approximately 36.0% in hereditary probands). Although the frequency of ASD was similar in deletion and duplication proband carriers (16.0% and 20.0%, respectively), the FSIQ was significantly lower (by 26.3 points) in the duplication probands with ASD. There also were lower head circumference and BMI measurements among duplication carriers, which is consistent with the findings of previous studies. The mean effect of the duplication on cognition is similar to that of the reciprocal deletion, but the variance in the duplication is significantly higher, with severe and mild subgroups not observed with the deletion. These results suggest that additional genetic and familial factors contribute to this variability. Additional studies will be necessary to characterize the predictors of cognitive deficits.

Carbon nanotube transistor based high-frequency electronics

NASA Astrophysics Data System (ADS)

Schroter, Michael

At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

Speech perception in noise with a harmonic complex excited vocoder.

PubMed

Churchill, Tyler H; Kan, Alan; Goupell, Matthew J; Ihlefeld, Antje; Litovsky, Ruth Y

2014-04-01

A cochlear implant (CI) presents band-pass-filtered acoustic envelope information by modulating current pulse train levels. Similarly, a vocoder presents envelope information by modulating an acoustic carrier. By studying how normal hearing (NH) listeners are able to understand degraded speech signals with a vocoder, the parameters that best simulate electric hearing and factors that might contribute to the NH-CI performance difference may be better understood. A vocoder with harmonic complex carriers (fundamental frequency, f0 = 100 Hz) was used to study the effect of carrier phase dispersion on speech envelopes and intelligibility. The starting phases of the harmonic components were randomly dispersed to varying degrees prior to carrier filtering and modulation. NH listeners were tested on recognition of a closed set of vocoded words in background noise. Two sets of synthesis filters simulated different amounts of current spread in CIs. Results showed that the speech vocoded with carriers whose starting phases were maximally dispersed was the most intelligible. Superior speech understanding may have been a result of the flattening of the dispersed-phase carrier's intrinsic temporal envelopes produced by the large number of interacting components in the high-frequency channels. Cross-correlogram analyses of auditory nerve model simulations confirmed that randomly dispersing the carrier's component starting phases resulted in better neural envelope representation. However, neural metrics extracted from these analyses were not found to accurately predict speech recognition scores for all vocoded speech conditions. It is possible that central speech understanding mechanisms are insensitive to the envelope-fine structure dichotomy exploited by vocoders.

Dysphagia, malnutrition and gastrointestinal problems in patients with mitochondrial disease caused by the m3243A>G mutation.

PubMed

de Laat, P; Zweers, H E E; Knuijt, S; Smeitink, J A M; Wanten, G J A; Janssen, M C H

2015-01-01

Previous research has shown that dysphagia and gastrointestinal problems occur frequently in carriers of the m.3243A>G mutation; however, the exact frequency and severity have not been determined. We hypothesise that adult carriers have an increased risk for malnutrition. In this observational study we evaluated the presence of gastrointestinal problems and dysphagia in 92 carriers of the m.3243A>G mutation. The severity of the general disease involvement was classified using the Newcastle Mitochondrial Disease Adult Scale (NMDAS). Gastrointestinal involvement, dysphagia and the risk for malnutrition were scored using the Gastrointestinal Symptoms Questionnaire and the Malnutrition Universal Screening Tool. Gastrointestinal symptoms and anthropometrics were compared with healthy controls. Our results show that the height, weight and body mass index (BMI) of these carriers were lower than the national average (p < 0.05). Seventy-nine carriers (86%) suffered from at least one gastrointestinal symptom, mainly flatulence or hard stools. Both frequency and severity of symptoms were significantly increased compared with reference data of healthy Dutch adults. Of the carriers, 45% reported (mostly mild) dysphagia. Solid foods cause more problems than liquids. A negative correlation between BMI and heteroplasmy levels in urinary epithelial cells (UEC) was present (Spearman correlation coefficient = - 0.319, p = 0.003). Dysphagia and gastrointestinal problems, especially constipation, are common symptoms in the total m.3243A>G carriers cohort and are not related to heteroplasmy levels in UEC or disease severity. The severity of gastrointestinal problems as well as overall disease severity is associated with an increased risk for malnutrition.

Attosecond control of electronic processes by intense light fields.

PubMed

Baltuska, A; Udem, Th; Uiberacker, M; Hentschel, M; Goulielmakis, E; Gohle, Ch; Holzwarth, R; Yakovlev, V S; Scrinzi, A; Hänsch, T W; Krausz, F

2003-02-06

The amplitude and frequency of laser light can be routinely measured and controlled on a femtosecond (10(-15) s) timescale. However, in pulses comprising just a few wave cycles, the amplitude envelope and carrier frequency are not sufficient to characterize and control laser radiation, because evolution of the light field is also influenced by a shift of the carrier wave with respect to the pulse peak. This so-called carrier-envelope phase has been predicted and observed to affect strong-field phenomena, but random shot-to-shot shifts have prevented the reproducible guiding of atomic processes using the electric field of light. Here we report the generation of intense, few-cycle laser pulses with a stable carrier envelope phase that permit the triggering and steering of microscopic motion with an ultimate precision limited only by quantum mechanical uncertainty. Using these reproducible light waveforms, we create light-induced atomic currents in ionized matter; the motion of the electronic wave packets can be controlled on timescales shorter than 250 attoseconds (250 x 10(-18) s). This enables us to control the attosecond temporal structure of coherent soft X-ray emission produced by the atomic currents--these X-ray photons provide a sensitive and intuitive tool for determining the carrier-envelope phase.

Time-domain measurement of optical transport in silicon micro-ring resonators.

PubMed

Pernice, Wolfram H P; Li, Mo; Tang, Hong X

2010-08-16

We perform time-domain measurements of optical transport dynamics in silicon nano-photonic devices. Using pulsed optical excitation the thermal and carrier induced optical nonlinearities of micro-ring resonators are investigated, allowing for identification of their individual contributions. Under pulsed excitation build-up of free carriers and heat in the waveguides leads to a beating oscillation of the cavity resonance frequency. When employing a burst of pulse trains shorter than the carrier life-time, the slower heating effect can be separated from the faster carrier effect. Our scheme provides a convenient way to thermally stabilize optical resonators for high-power time-domain applications and nonlinear optical conversion.

Inheritance of proportionate dwarfism in Angus cattle.

PubMed

Latter, M R; Latter, B D H; Wilkins, J F; Windsor, P A

2006-04-01

To determine the mode of inheritance of congenital proportionate dwarfism in Angus and Angus crossbred cattle, initially detected in two commercial beef herds in northern New South Wales. Matings of normal carrier sires to unrelated cows of diverse breeds, and of one carrier sire to his unaffected daughters. An unrelated Piedmontese bull was also mated to unaffected daughters of the carrier sires. Two carrier Angus bulls and nine unaffected daughters, all of whom were completely indistinguishable from normal animals, were purchased for controlled breeding studies under known nutritional and disease conditions. Affected and carrier individuals were examined for the presence of obvious chromosomal abnormalities. Angus dwarfism has been successfully reproduced under controlled experimental conditions over successive years using unrelated dams and is undoubtedly heritable. The high frequency of occurrence of affected individuals (23/61 = 0.38 +/- .06) among the progeny of matings of the Angus sires to unrelated females of diverse breeding is not compatible with recessive inheritance, because of the negligible frequency of proportionate dwarfism in the breeds of the dams. Both paternal and maternal transmission of the defect was demonstrated, so that imprinting in the strict sense of a gene that is only expressed when received from the male parent appears not to be involved. Tested individuals showed no evidence of gross chromosomal abnormality. Dominant autosomal inheritance with incomplete penetrance was indicated by the lack of expression of the defective gene in the two Angus sires and in three unaffected daughters who produced dwarf calves from matings to the Piedmontese bull. The mode of inheritance is that of a single autosomal dominant gene with a penetrance coefficient of 0.75 +/- 0.12, estimated from the observed incidence of 23/61 affected offspring of the two carrier Angus bulls mated to unrelated dams. Simple genetic models involving either (i) an unstable mutant which changes at high frequency to the expressed dominant dwarfing allele during gametogenesis, or (ii) a dominant allele with penetrance determined by an unlinked modifying locus, are shown to be compatible with the experimental data. Both models indicate that penetrance of the dwarfing gene may possibly be higher in matings involving carrier daughters of the two Angus bulls.

47 CFR 61.22 - Composition of tariffs.

Code of Federal Regulations, 2010 CFR

2010-10-01

...Perfect 5.1, Microsoft Word 6, or Microsoft Word 97 software. No diskettes shall contain more than one... clearly labelled with the carrier's name, Tariff Number, software used, and the date of submission. When... defined in § 1.4(e)(2) of this chapter. (d) Domestic and international nondominant carriers subject to the...

47 CFR 54.416 - Annual certifications by eligible telecommunications carriers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Administrator the following annual certifications, under penalty of perjury, relating to the Lifeline program... Administrator as part of the carrier's submission of annual re-certification data pursuant to this section. In... eligibility databases, as defined in § 54.410(b)(1)(i)(A) or (c)(1)(i)(A), the representative must attest...

47 CFR 54.416 - Annual certifications by eligible telecommunications carriers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Administrator the following annual certifications, under penalty of perjury, relating to the Lifeline program... Administrator as part of the carrier's submission of annual re-certification data pursuant to this section. In... eligibility databases, as defined in § 54.410(b)(1)(i)(A) or (c)(1)(i)(A), the representative must attest...

47 CFR 54.416 - Annual certifications by eligible telecommunications carriers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Administrator the following annual certifications, under penalty of perjury, relating to the Lifeline program... Administrator as part of the carrier's submission of annual re-certification data pursuant to this section. In... eligibility databases, as defined in § 54.410(b)(1)(i)(A) or (c)(1)(i)(A), the representative must attest...

Second year technical report on-board processing for future satellite communications systems

NASA Technical Reports Server (NTRS)

Brandon, W. T.; Green, W. K.; Hoffman, M.; Jean, P. N.; Neal, W. R.; White, B. E.

1980-01-01

Advanced baseband and microwave switching techniques for large domestic communications satellites operating in the 30/20 GHz frequency bands are discussed. The nominal baseband processor throughput is one million packets per second (1.6 Gb/s) from one thousand T1 carrier rate customer premises terminals. A frequency reuse factor of sixteen is assumed by using 16 spot antenna beams with the same 100 MHz bandwidth per beam and a modulation with a one b/s per Hz bandwidth efficiency. Eight of the beams are fixed on major metropolitan areas and eight are scanning beams which periodically cover the remainder of the U.S. under dynamic control. User signals are regenerated (demodulated/remodulated) and message packages are reformatted on board. Frequency division multiple access and time division multiplex are employed on the uplinks and downlinks, respectively, for terminals within the coverage area and dwell interval of a scanning beam. Link establishment and packet routing protocols are defined. Also described is a detailed design of a separate 100 x 100 microwave switch capable of handling nonregenerated signals occupying the remaining 2.4 GHz bandwidth with 60 dB of isolation, at an estimated weight and power consumption of approximately 400 kg and 100 W, respectively.

Second year technical report on-board processing for future satellite communications systems

NASA Astrophysics Data System (ADS)

Brandon, W. T.; Green, W. K.; Hoffman, M.; Jean, P. N.; Neal, W. R.; White, B. E.

1980-10-01

Advanced baseband and microwave switching techniques for large domestic communications satellites operating in the 30/20 GHz frequency bands are discussed. The nominal baseband processor throughput is one million packets per second (1.6 Gb/s) from one thousand T1 carrier rate customer premises terminals. A frequency reuse factor of sixteen is assumed by using 16 spot antenna beams with the same 100 MHz bandwidth per beam and a modulation with a one b/s per Hz bandwidth efficiency. Eight of the beams are fixed on major metropolitan areas and eight are scanning beams which periodically cover the remainder of the U.S. under dynamic control. User signals are regenerated (demodulated/remodulated) and message packages are reformatted on board. Frequency division multiple access and time division multiplex are employed on the uplinks and downlinks, respectively, for terminals within the coverage area and dwell interval of a scanning beam. Link establishment and packet routing protocols are defined. Also described is a detailed design of a separate 100 x 100 microwave switch capable of handling nonregenerated signals occupying the remaining 2.4 GHz bandwidth with 60 dB of isolation, at an estimated weight and power consumption of approximately 400 kg and 100 W, respectively.

Purified frequency modulation of a quantum cascade laser with an all-optical approach.

PubMed

Peng, Chen; Zhou, Haijun; Zhu, Liguo; Chen, Tao; Liu, Qiao; Wang, Detian; Li, Jiang; Peng, Qixian; Chen, Gang; Li, Zeren

2017-11-01

Purified frequency modulation (FM) is demonstrated in a standard middle-infrared quantum cascade laser by illuminating its front facet with two near-infrared (NIR) lasers. A 2 mW laser at 1550 nm is utilized to modulate the amplitude and frequency of a quantum cascade laser, and the associated amplitude modulation (AM) is suppressed by a 1.85 mW laser at 850 nm. Due to the hot carrier effect and the increment of electron temperature, the AM has been decreased. In addition, the free carrier concentration increases in the active region due to the two NIR illuminations, which enhance the FM. Purified FM is beneficial in improving the signal fidelity for free-space optical communication and high-speed FM spectroscopy.

A study on the co- and adjacent channel protection requirements for mobile satellite ACSSB modulation

NASA Technical Reports Server (NTRS)

Sydor, John T.

1988-01-01

Samples of speech modulated by narrowband frequency modulation (NBFM) (cellular) and amplitude companded single sideband (ACSSB) radios were subjected to simulated co- and adjacent channel interference environments typical of proposed frequency division multiple access (FDMA) mobile satellite systems. These samples were then listened to by a group of evaluators whose subjective responses to the samples were used to produce a series of graphs showing the relationship between subjective acceptability, carrier to noise density (C/No), carrier to interference ratio (C/I), and frequency offset. The results show that in a mobile satellite environment, ACSSB deteriorates more slowly than NBFM. The co- and adjacent channel protection ratios for both modulation techniques were roughly the same, even though the mechanism for signal deterioration is different.

Doppler-multipath tolerant voice communication

NASA Astrophysics Data System (ADS)

Harris, R. M.

Line of sight communication between high performance aircraft has been found to be subject to a peculiar form of multipath radio wave propagation - Doppler multipath. It degrades analogue voice reception on the standard fit ultrahigh frequency radio, producing low frequency random noise and warbling. Various modifications were carried out on the aircraft's communications system, but the problem remained. All the evidence points to a natural phenomenon. The reported observations are corroborated by theoretical studies and laboratory simulations of multipath radio wave propagation between two points moving relative to a diffusely scattering reflector. Theoretical predictions of Rician fading have explained the disruption of speech transmitted using conventional dsb(am) modulation. This also indicated suppressing the carrier as a radical cure. Double sideband suppressed carrier radios have been developed for airborne evaluation in comparison with standard dsb(am). The air to air flying trials proved the superior performance of the suppressed carrier system under conditions of Doppler multipath.

47 CFR 73.756 - System specifications for double-sideband (DBS) modulated emissions in the HF broadcasting service.

Code of Federal Regulations, 2014 CFR

2014-10-01

.... Nominal carrier frequencies shall be integral multiples of 5 kHz. (2) Audio-frequency band. The upper limit of the audio-frequency band (at—3 dB) of the transmitter shall not exceed 4.5 kHz and the lower... processing. If audio-frequency signal processing is used, the dynamic range of the modulating signal shall be...

47 CFR 73.756 - System specifications for double-sideband (DBS) modulated emissions in the HF broadcasting service.

Code of Federal Regulations, 2012 CFR

2012-10-01

.... Nominal carrier frequencies shall be integral multiples of 5 kHz. (2) Audio-frequency band. The upper limit of the audio-frequency band (at—3 dB) of the transmitter shall not exceed 4.5 kHz and the lower... processing. If audio-frequency signal processing is used, the dynamic range of the modulating signal shall be...

47 CFR 73.756 - System specifications for double-sideband (DBS) modulated emissions in the HF broadcasting service.

Code of Federal Regulations, 2011 CFR

2011-10-01

.... Nominal carrier frequencies shall be integral multiples of 5 kHz. (2) Audio-frequency band. The upper limit of the audio-frequency band (at—3 dB) of the transmitter shall not exceed 4.5 kHz and the lower... processing. If audio-frequency signal processing is used, the dynamic range of the modulating signal shall be...

47 CFR 73.756 - System specifications for double-sideband (DBS) modulated emissions in the HF broadcasting service.

Code of Federal Regulations, 2013 CFR

2013-10-01

.... Nominal carrier frequencies shall be integral multiples of 5 kHz. (2) Audio-frequency band. The upper limit of the audio-frequency band (at—3 dB) of the transmitter shall not exceed 4.5 kHz and the lower... processing. If audio-frequency signal processing is used, the dynamic range of the modulating signal shall be...

High Electron Mobility Transistor Structures on Sapphire Substrates Using CMOS Compatible Processing Techniques

NASA Technical Reports Server (NTRS)

Mueller, Carl; Alterovitz, Samuel; Croke, Edward; Ponchak, George

2004-01-01

System-on-a-chip (SOC) processes are under intense development for high-speed, high frequency transceiver circuitry. As frequencies, data rates, and circuit complexity increases, the need for substrates that enable high-speed analog operation, low-power digital circuitry, and excellent isolation between devices becomes increasingly critical. SiGe/Si modulation doped field effect transistors (MODFETs) with high carrier mobilities are currently under development to meet the active RF device needs. However, as the substrate normally used is Si, the low-to-modest substrate resistivity causes large losses in the passive elements required for a complete high frequency circuit. These losses are projected to become increasingly troublesome as device frequencies progress to the Ku-band (12 - 18 GHz) and beyond. Sapphire is an excellent substrate for high frequency SOC designs because it supports excellent both active and passive RF device performance, as well as low-power digital operations. We are developing high electron mobility SiGe/Si transistor structures on r-plane sapphire, using either in-situ grown n-MODFET structures or ion-implanted high electron mobility transistor (HEMT) structures. Advantages of the MODFET structures include high electron mobilities at all temperatures (relative to ion-implanted HEMT structures), with mobility continuously improving to cryogenic temperatures. We have measured electron mobilities over 1,200 and 13,000 sq cm/V-sec at room temperature and 0.25 K, respectively in MODFET structures. The electron carrier densities were 1.6 and 1.33 x 10(exp 12)/sq cm at room and liquid helium temperature, respectively, denoting excellent carrier confinement. Using this technique, we have observed electron mobilities as high as 900 sq cm/V-sec at room temperature at a carrier density of 1.3 x 10(exp 12)/sq cm. The temperature dependence of mobility for both the MODFET and HEMT structures provides insights into the mechanisms that allow for enhanced electron mobility as well as the processes that limit mobility, and will be presented.

Frequency comb based on a narrowband Yb-fiber oscillator: pre-chirp management for self-referenced carrier envelope offset frequency stabilization.

PubMed

Lim, Jinkang; Chen, Hung-Wen; Chang, Guoqing; Kärtner, Franz X

2013-02-25

Laser frequency combs are normally based on mode-locked oscillators emitting ultrashort pulses of ~100-fs or shorter. In this paper, we present a self-referenced frequency comb based on a narrowband (5-nm bandwidth corresponding to 415-fs transform-limited pulses) Yb-fiber oscillator with a repetition rate of 280 MHz. We employ a nonlinear Yb-fiber amplifier to both amplify the narrowband pulses and broaden their optical spectrum. To optimize the carrier envelope offset frequency (fCEO), we optimize the nonlinear pulse amplification by pre-chirping the pulses at the amplifier input. An optimum negative pre-chirp exists, which produces a signal-to-noise ratio of 35 dB (100 kHz resolution bandwidth) for the detected fCEO. We phase stabilize the fCEO using a feed-forward method, resulting in 0.64-rad (integrated from 1 Hz to 10 MHz) phase noise for the in-loop error signal. This work demonstrates the feasibility of implementing frequency combs from a narrowband oscillator, which is of particular importance for realizing large line-spacing frequency combs based on multi-GHz oscillators usually emitting long (>200 fs) pulses.

Studying effect of carrier fluid viscosity in magnetite based ferrofluids using optical tweezers

NASA Astrophysics Data System (ADS)

Savitha, S.; Iyengar, Shruthi S.; Ananthamurthy, Sharath; Bhattacharya, Sarbari

2018-02-01

Ferrofluids with varying viscosities of carrier fluids have been prepared with magnetite (Fe3O4) nanoparticles. The nanoparticles were synthesized by chemical co-precipitation and characterized using X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). They were found to be nearly spherical in shape with an almost uniform size of 13nm. The superparamagnetic nature of the water based ferrofluids at room temperature was established by SQUID magnetometry. Dynamic light scattering (DLS) was carried out to establish the size of the nanoparticle clusters in the ferrofluids synthesized. The results indicate an increase in cluster size with increase in carrier fluid viscosity. This is supported by results from Raman Spectroscopy. A further attempt to characterise these ferrofluids was made by studying the behaviour of well characterised non-magnetic micron sized probes that are optically trapped while suspended in the ferrofluid. An increase in carrier fluid viscosity results in a decrease in corner frequency when only the carrier fluid is used as the suspending medium. When the magnetic component is also present the corner frequency is higher than with just the carrier fluid. This relative increase happens at all laser powers at the trapping plane. This trend is also found to be independent of the size and material of the probe particle. Comparisons of various parameters that influence optical trapping lead us to believe that the enhancement could be due to a directed motion of the magnetic clusters in the presence of an optical trap.

47 CFR 25.275 - Particulars of operation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... part will normally specify only the frequency bands authorized for transmission and/or reception of the station. (b) When authorized frequency bands are specified in the station authorization, the licensee is...

47 CFR 25.275 - Particulars of operation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... part will normally specify only the frequency bands authorized for transmission and/or reception of the station. (b) When authorized frequency bands are specified in the station authorization, the licensee is...

47 CFR 25.275 - Particulars of operation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... part will normally specify only the frequency bands authorized for transmission and/or reception of the station. (b) When authorized frequency bands are specified in the station authorization, the licensee is...

47 CFR 25.275 - Particulars of operation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... part will normally specify only the frequency bands authorized for transmission and/or reception of the station. (b) When authorized frequency bands are specified in the station authorization, the licensee is...

47 CFR 25.275 - Particulars of operation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... part will normally specify only the frequency bands authorized for transmission and/or reception of the station. (b) When authorized frequency bands are specified in the station authorization, the licensee is...

Do piperacillin/tazobactam and other antibiotics with inhibitory activity against Clostridium difficile reduce the risk for acquisition of C. difficile colonization?

PubMed

Kundrapu, Sirisha; Sunkesula, Venkata C K; Jury, Lucy A; Cadnum, Jennifer L; Nerandzic, Michelle M; Musuuza, Jackson S; Sethi, Ajay K; Donskey, Curtis J

2016-04-18

Systemic antibiotics vary widely in in vitro activity against Clostridium difficile. Some agents with activity against C. difficile (e.g., piperacillin/tazobactam) inhibit establishment of colonization in mice. We tested the hypothesis that piperacillin/tazobactam and other agents with activity against C. difficile achieve sufficient concentrations in the intestinal tract to inhibit colonization in patients. Point-prevalence culture surveys were conducted to compare the frequency of asymptomatic rectal carriage of toxigenic C. difficile among patients receiving piperacillin/tazobactam or other inhibitory antibiotics (e.g. ampicillin, linezolid, carbapenems) versus antibiotics lacking activity against C. difficile (e.g., cephalosporins, ciprofloxacin). For a subset of patients, in vitro inhibition of C. difficile (defined as a reduction in concentration after inoculation of vegetative C. difficile into fresh stool suspensions) was compared among antibiotic treatment groups. Of 250 patients, 32 (13 %) were asymptomatic carriers of C. difficile. In comparison to patients receiving non-inhibitory antibiotics or prior antibiotics within 90 days, patients currently receiving piperacillin/tazobactam were less likely to be asymptomatic carriers (1/36, 3 versus 7/36, 19 and 15/69, 22 %, respectively; P = 0.024) and more likely to have fecal suspensions with in vitro inhibitory activity against C. difficile (20/28, 71 versus 3/11, 27 and 4/26, 15 %; P = 0.03). Patients receiving other inhibitory antibiotics were not less likely to be asymptomatic carriers than those receiving non-inhibitory antibiotics. Our findings suggest that piperacillin/tazobactam achieves sufficient concentrations in the intestinal tract to inhibit C. difficile colonization during therapy.

Young Adult Female Fragile X Premutation Carriers Show Age- and Genetically-Modulated Cognitive Impairments

ERIC Educational Resources Information Center

Goodrich-Hunsaker, Naomi J.; Wong, Ling M.; McLennan, Yingratana; Srivastava, Siddharth; Tassone, Flora; Harvey, Danielle; Rivera, Susan M.; Simon, Tony J.

2011-01-01

The high frequency of the fragile X premutation in the general population and its emerging neurocognitive implications highlight the need to investigate the effects of the premutation on lifespan cognitive development. Until recently, cognitive function in fragile X premutation carriers (fXPCs) was presumed to be unaffected by the mutation. Here…

Experimental implementation of optical clockwork without carrier-envelope phase control.

PubMed

Mücke, O D; Kuzucu, O; Wong, F N C; Ippen, E P; Kärtner, F X; Foreman, S M; Jones, D J; Ma, L S; Hall, J L; Ye, J

2004-12-01

We demonstrate optical clockwork without the need for carrier-envelope phase control by use of sum-frequency generation between a continuous-wave optical parametric oscillator at 3.39 microm and a femtosecond mode-locked Ti:sapphire laser with two strong spectral peaks at 834 and 670 nm, a spectral difference matched by the 3.39-microm radiation.

14 CFR 171.111 - Ground standards and tolerances.

Code of Federal Regulations, 2010 CFR

2010-01-01

... line. (2) The depth of modulation of the radio frequency carrier due to the 1020 Hz identification... approval and must be maintained during operation of the SDF. (a) Frequency. (1) The SDF must operate on odd tenths or odd tenths plus a twentieth MHz within the frequency band 108.1 MHz to 111.95 MHz. The...

Nationwide genetic testing towards eliminating Lafora disease from Miniature Wirehaired Dachshunds in the United Kingdom.

PubMed

Ahonen, Saija; Seath, Ian; Rusbridge, Clare; Holt, Susan; Key, Gill; Wang, Travis; Wang, Peixiang; Minassian, Berge A

2018-01-01

Canine DNA-testing has become an important tool in purebred dog breeding and many breeders use genetic testing results when planning their breeding strategies. In addition, information obtained from testing of hundreds dogs in one breed gives valuable information about the breed-wide genotype frequency of disease associated allele. Lafora disease is a late onset, recessively inherited genetic disease which is diagnosed in Miniature Wirehaired Dachshunds (MWHD). It is one of the most severe forms of canine epilepsy leading to neurodegeneration and, frequently euthanasia within a few years of diagnosis. Canine Lafora disease is caused by a dodecamer repeat expansion mutation in the NHLRC1 gene and a DNA test is available to identify homozygous dogs at risk, carriers and dogs free of the mutation. Blood samples were collected from 733 MWHDs worldwide, mostly of UK origin, for canine Lafora disease testing. Among the tested MWHD population 7.0% were homozygous for the mutation and at risk for Lafora disease. In addition, 234 dogs were heterozygous, indicating a carrier frequency of 31.9% in the tested population. Among the tested MWHDs, the mutant allele frequency was 0.2. In addition, data from the tested dogs over 6 years (2012-2017) indicated that the frequency of the homozygous and carrier dogs has decreased from 10.4% to 2.7% and 41.5% to 25.7%, respectively among MWHDs tested. As a consequence, the frequency of dogs free of the mutation has increased from 48.1% to 71.6%. This study provides valuable data for the MWHD community and shows that the DNA test is a useful tool for the breeders to prevent occurrence of Lafora disease in MWHDs. DNA testing has, over 6 years, helped to decrease the frequency of carriers and dogs at risk. Additionally, the DNA test can continue to be used to slowly eradicate the disease-causing mutation in the breed. However, this should be done carefully, over time, to avoid further compromising the genetic diversity of the breed. The DNA test also provides a diagnostic tool for veterinarians if they are presented with a dog that shows clinical signs associated with canine Lafora disease.

146-GHz millimeter-wave radio-over-fiber photonic wireless transmission system.

PubMed

Fice, M J; Rouvalis, E; van Dijk, F; Accard, A; Lelarge, F; Renaud, C C; Carpintero, G; Seeds, A J

2012-01-16

We report the experimental implementation of a wireless transmission system with a 146-GHz carrier frequency which is generated by optical heterodyning the two modes from a monolithically integrated quantum dash dual-DFB source. The monolithic structure of the device and the inherent low noise characteristics of quantum dash gain material allow us to demonstrate the transmission of a 1 Gbps ON-OFF keyed data signal with the two wavelengths in a free-running state at 146-GHz carrier wave frequency. The tuning range of the device fully covers the W-band (75 - 110 GHz) and the F-band (90 - 140 GHz).

The theory and implementation of a high quality pulse width modulated waveform synthesiser applicable to voltage FED inverters

NASA Astrophysics Data System (ADS)

Lower, Kim Nigel

1985-03-01

Modulation processes associated with the digital implementation of pulse width modulation (PWM) switching strategies were examined. A software package based on a portable turnkey structure is presented. Waveform synthesizer implementation techniques are reviewed. A three phase PWM waveform synthesizer for voltage fed inverters was realized. It is based on a constant carrier frequency of 18 kHz and a regular sample, single edge, asynchronous PWM switching scheme. With high carrier frequencies, it is possible to utilize simple switching strategies and as a consequence, many advantages are highlighted, emphasizing the importance to industrial and office markets.

Accuracy and Precision of USNO GPS Carrier-Phase Time Transfer

DTIC Science & Technology

2010-01-01

values. Comparison measures used include estimates obtained from two-way satellite time/frequency transfer ( TWSTFT ), and GPS-based estimates obtained...the IGS are used as a benchmark in the computation. Frequency values have a few times 10 -15 fractional frequency uncertainty. TWSTFT values confirm...obtained from two-way satellite time/frequency transfer ( TWSTFT ), BIPM Circular T, and the International GNSS Service (IGS). At present, it is known that

Dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate

NASA Astrophysics Data System (ADS)

Pal, P.; Ghosh, A.

2016-07-01

In this paper, we have studied the dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate. Structural and thermal properties have been examined using X-ray diffraction and differential scanning calorimetry, respectively. We have analyzed the complex conductivity spectra by using power law model coupled with the contribution of electrode polarization at low frequencies and high temperatures. The temperature dependence of the ionic conductivity and crossover frequency exhibits Vogel-Tammann-Fulcher type behavior indicating a strong coupling between the ionic and the polymer chain segmental motions. The scaling of the ac conductivity indicates that relaxation dynamics of charge carriers follows a common mechanism for all temperatures and ethylene carbonate concentrations. The analysis of the ac conductivity also shows the existence of a nearly constant loss in these polymer electrolytes at low temperatures and high frequencies. The fraction of free anions and ion pairs in polymer electrolyte have been obtained from the analysis of Fourier transform infrared spectra. It is observed that these quantities influence the behavior of the composition dependence of the ionic conductivity.

Dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pal, P.; Ghosh, A., E-mail: sspag@iacs.res.in

2016-07-28

In this paper, we have studied the dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate. Structural and thermal properties have been examined using X-ray diffraction and differential scanning calorimetry, respectively. We have analyzed the complex conductivity spectra by using power law model coupled with the contribution of electrode polarization at low frequencies and high temperatures. The temperature dependence of the ionic conductivity and crossover frequency exhibits Vogel-Tammann-Fulcher type behavior indicating a strong coupling between the ionic and the polymer chain segmental motions. The scaling of the ac conductivity indicates that relaxation dynamicsmore » of charge carriers follows a common mechanism for all temperatures and ethylene carbonate concentrations. The analysis of the ac conductivity also shows the existence of a nearly constant loss in these polymer electrolytes at low temperatures and high frequencies. The fraction of free anions and ion pairs in polymer electrolyte have been obtained from the analysis of Fourier transform infrared spectra. It is observed that these quantities influence the behavior of the composition dependence of the ionic conductivity.« less

Photo-Carrier Multi-Dynamical Imaging at the Nanometer Scale in Organic and Inorganic Solar Cells.

PubMed

Fernández Garrillo, Pablo A; Borowik, Łukasz; Caffy, Florent; Demadrille, Renaud; Grévin, Benjamin

2016-11-16

Investigating the photocarrier dynamics in nanostructured and heterogeneous energy materials is of crucial importance from both fundamental and technological points of view. Here, we demonstrate how noncontact atomic force microscopy combined with Kelvin probe force microscopy under frequency-modulated illumination can be used to simultaneously image the surface photopotential dynamics at different time scales with a sub-10 nm lateral resolution. The basic principle of the method consists in the acquisition of spectroscopic curves of the surface potential as a function of the illumination frequency modulation on a two-dimensional grid. We show how this frequency-spectroscopy can be used to probe simultaneously the charging rate and several decay processes involving short-lived and long-lived carriers. With this approach, dynamical images of the trap-filling, trap-delayed recombination and nongeminate recombination processes have been acquired in nanophase segregated organic donor-acceptor bulk heterojunction thin films. Furthermore, the spatial variation of the minority carrier lifetime has been imaged in polycrystalline silicon thin films. These results establish two-dimensional multidynamical photovoltage imaging as a universal tool for local investigations of the photocarrier dynamics in photoactive materials and devices.

Large-Velocity Saturation in Thin-Film Black Phosphorus Transistors.

PubMed

Chen, Xiaolong; Chen, Chen; Levi, Adi; Houben, Lothar; Deng, Bingchen; Yuan, Shaofan; Ma, Chao; Watanabe, Kenji; Taniguchi, Takashi; Naveh, Doron; Du, Xu; Xia, Fengnian

2018-05-22

A high saturation velocity semiconductor is appealing for applications in electronics and optoelectronics. Thin-film black phosphorus (BP), an emerging layered semiconductor, shows a high carrier mobility and strong mid-infrared photoresponse at room temperature. Here, we report the observation of high intrinsic saturation velocity in 7 to 11 nm thick BP for both electrons and holes as a function of charge-carrier density, temperature, and crystalline direction. We distinguish a drift velocity transition point due to the competition between the electron-impurity and electron-phonon scatterings. We further achieve a room-temperature saturation velocity of 1.2 (1.0) × 10 7 cm s -1 for hole (electron) carriers at a critical electric field of 14 (13) kV cm -1 , indicating an intrinsic current-gain cutoff frequency ∼20 GHz·μm for radio frequency applications. Moreover, the current density is as high as 580 μA μm -1 at a low electric field of 10 kV cm -1 . Our studies demonstrate that thin-film BP outperforms silicon in terms of saturation velocity and critical field, revealing its great potential in radio-frequency electronics, high-speed mid-infrared photodetectors, and optical modulators.

Frequency of adult type-associated lactase persistence LCT-13910C/T genotypes in the Czech/Slav and Czech Roma/Gypsy populations

PubMed Central

Hubácek, Jaroslav A.; Adámková, Věra; Šedová, Lenka; Olišarová, Věra; Adámek, Václav; Tóthová, Valérie

2017-01-01

Abstract Lactase non-persistence (leading to primary lactose intolerance) is a genetically dependent inability to digest lactose in adulthood. As part of the human adaptation to dairying, the human lactase LCT-13910C/T mutation (which propagates adult expression of lactase) developed, spread and participated in the adaptation to dairying. This variant is associated with lactase activity persistence, and its carriers are able to digest lactose. We compared the frequencies of lactase 13910C/T (rs4988235) genotypes in Czechs/Slavs (N = 288) and Czech Gypsies/Roma (N = 300), two ethnically different groups where this polymorphism has not yet been analysed. Allelic frequencies significantly differed between the populations (p < 0.0001). In Czechs/Slavs, the lactase persistence T allele was present in 76% of the individuals, which is in agreement with frequencies among geographically neighbouring populations. In the Czech Gypsy/Roma population, only 27% of the adults were carriers of at least one lactase persistence allele, similar to the Indian population. In agreement with this result, dairy product consumption was reported by 70.5% of Czechs/Slavs and 39.0% of the Czech Gypsy/Roma population. Both in the Czech Gypsy/Roma and in the Czech/Slavs populations, the presence of carriers of the lactase persistence allele was similar in subjects self-reporting the consumption of unfermented/fresh milk, in comparison to the others. PMID:28497837

Frequency of adult type-associated lactase persistence LCT-13910C/T genotypes in the Czech/Slav and Czech Roma/Gypsy populations.

PubMed

Hubácek, Jaroslav A; Adámková, Věra; Šedová, Lenka; Olišarová, Věra; Adámek, Václav; Tóthová, Valérie

2017-01-01

Lactase non-persistence (leading to primary lactose intolerance) is a genetically dependent inability to digest lactose in adulthood. As part of the human adaptation to dairying, the human lactase LCT-13910C/T mutation (which propagates adult expression of lactase) developed, spread and participated in the adaptation to dairying. This variant is associated with lactase activity persistence, and its carriers are able to digest lactose. We compared the frequencies of lactase 13910C/T (rs4988235) genotypes in Czechs/Slavs (N = 288) and Czech Gypsies/Roma (N = 300), two ethnically different groups where this polymorphism has not yet been analysed. Allelic frequencies significantly differed between the populations (p < 0.0001). In Czechs/Slavs, the lactase persistence T allele was present in 76% of the individuals, which is in agreement with frequencies among geographically neighbouring populations. In the Czech Gypsy/Roma population, only 27% of the adults were carriers of at least one lactase persistence allele, similar to the Indian population. In agreement with this result, dairy product consumption was reported by 70.5% of Czechs/Slavs and 39.0% of the Czech Gypsy/Roma population. Both in the Czech Gypsy/Roma and in the Czech/Slavs populations, the presence of carriers of the lactase persistence allele was similar in subjects self-reporting the consumption of unfermented/fresh milk, in comparison to the others.

Multiplexing Readout of TES Microcalorimeters Based on Analog Baseband Feedback

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takei, Y.; Yamasaki, N.Y; Mitsuda, K.

2009-12-16

A TES microcalorimeter array is a promising spectrometer with excellent energy resolution and a moderate imaging capability. To realize a large format array in space, multiplexing the TES signals at the low tempersture stage is mandatory. We are developing frequency division multiplexing (FDM) based on baseband feedback technique. In FDM, each TES is AC-biased with a different carrier frequency. Signals from several pixels are summed and then read out by one SQUID. The maximum number of multiplexed pixels are limited by the frequency band in which the SQUID can be operated in a flux-locked loop, which is {approx}1 MHz withmore » standard flux-locked loop circuit. In the baseband feedback, the signal ({approx}10 kHz band) from the TES is once demodulated. Then a reconstructed copy of the modulated signal with an appropriate phase is fed back to the SQUID input coil to maintain an approximately constant magnetic flux. This can be implemented even for large cable delays and automatically suppresses the carrier. We developed a prototype electronics for the baseband feedback based on an analog phase sensitive detector (PSD) and a multiplier. Combined with Seiko 80-SSA SQUID amp, open-loop gain of 8 has been obtained for 10 kHz baseband signal at 5 MHz carrier frequency, with a moderate noise contribution of 27pA/{radical}(Hz) at input.« less

Instantaneous Real-Time Kinematic Decimeter-Level Positioning with BeiDou Triple-Frequency Signals over Medium Baselines.

PubMed

He, Xiyang; Zhang, Xiaohong; Tang, Long; Liu, Wanke

2015-12-22

Many applications, such as marine navigation, land vehicles location, etc., require real time precise positioning under medium or long baseline conditions. In this contribution, we develop a model of real-time kinematic decimeter-level positioning with BeiDou Navigation Satellite System (BDS) triple-frequency signals over medium distances. The ambiguities of two extra-wide-lane (EWL) combinations are fixed first, and then a wide lane (WL) combination is reformed based on the two EWL combinations for positioning. Theoretical analysis and empirical analysis is given of the ambiguity fixing rate and the positioning accuracy of the presented method. The results indicate that the ambiguity fixing rate can be up to more than 98% when using BDS medium baseline observations, which is much higher than that of dual-frequency Hatch-Melbourne-Wübbena (HMW) method. As for positioning accuracy, decimeter level accuracy can be achieved with this method, which is comparable to that of carrier-smoothed code differential positioning method. Signal interruption simulation experiment indicates that the proposed method can realize fast high-precision positioning whereas the carrier-smoothed code differential positioning method needs several hundreds of seconds for obtaining high precision results. We can conclude that a relatively high accuracy and high fixing rate can be achieved for triple-frequency WL method with single-epoch observations, displaying significant advantage comparing to traditional carrier-smoothed code differential positioning method.

Different segregation patterns in five carriers due to a pericentric inversion of chromosome 1.

PubMed

Luo, Yuqin; Xu, Chenming; Sun, Yixi; Wang, Liya; Chen, Songchang; Jin, Fan

2014-12-01

Pericentric inversion can produce recombinant gametes; however, meiotic segregation studies on the relationship between the frequency of recombinants and the inverted segment size are rare. Triple-color fluorescence in situ hybridization (FISH) was performed to analyze the meiotic behavior in five inv(1) carriers with different breakpoints. Recombination gametes were absent in Patient 1, whereas the percentages of the recombinants in Patients 2, 3, 4, and 5 were of 9.2%, 15.3%, 17.3%, and 40.9%, respectively. A significant difference was present for the frequencies of the recombinant spermatozoa among the five patients (p < 0.001). For each patient, the frequency of the two types of recombinant gametes (dup(1p)/del(1q) or del(1p)/dup(1q)) did not exhibit a significant difference in comparison with the expected 1:1 ratio (p > 0.05). The meiotic segregation of nine inv(1) carriers (including those presented in this paper) is now available. A significant correlation was discovered between the rate of recombination and the proportion of the chromosome implicated in the inversion (R = 0.9435, p < 0.001). The frequency of the recombinant gametes was directly related to the proportion of the chromosome that was inverted. Sperm-FISH allowed an additional comprehension of the patterns of meiotic segregation and provided accurate genetic counseling.

College Carrier Current: A Survey of 208 Campus-Limited Radio Stations.

ERIC Educational Resources Information Center

Broadcast Inst. of North America, New York, NY.

The purpose of this survey was to determine the extent to which carrier current radio has become a medium which can link and unify relatively small, well-defined groups in an effective and inexpensive way. The survey focused upon the auspices, structure, affiliation, day-to-day managerial responsibility, and administrative liaison of the stations;…

47 CFR 1.47 - Service of documents and proof of service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... carrier and interconnected VoIP provider, as defined in § 54.5 of this chapter, that is subject to the... requirements of the Commission may be made for and on behalf of such carrier or interconnected VoIP provider in... interconnected VoIP provider and its designated agents, a name, business address, telephone or voicemail number...

Investigation of traveler acceptance factors in short haul air carrier operations

NASA Technical Reports Server (NTRS)

Kuhlthau, A. R.; Jacobson, I. D.

1972-01-01

The development of a mathematical model for human reaction to variables involved in transportation systems is discussed. The techniques, activities, and results related to defining certain specific inputs to the model are presented. A general schematic diagram of the problem solution is developed. The application of the model to short haul air carrier operations is examined.

Feasibility of graphene CRLH metamaterial waveguides and leaky wave antennas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, Derrick A.; Itoh, Tatsuo; Hon, Philip W. C.

2016-07-07

The feasibility of composite right/left-handed (CRLH) metamaterial waveguides based upon graphene plasmons is demonstrated via numerical simulation. Designs are presented that operate in the terahertz frequency range along with their various dimensions. Dispersion relations, radiative and free-carrier losses, and free-carrier based tunability are characterized. Finally, the radiative characteristics are evaluated, along with its feasibility for use as a leaky-wave antenna. While CRLH waveguides are feasible in the terahertz range, their ultimate utility will require precise nanofabrication, and excellent quality graphene to mitigate free-carrier losses.

Terahertz radiation from accelerating charge carriers in graphene under ultrafast photoexcitation

NASA Astrophysics Data System (ADS)

Rustagi, Avinash; Stanton, C. J.

2016-11-01

We study the generation of terahertz (THz) radiation from the acceleration of ultrafast photoexcited charge carriers in graphene in the presence of a dc electric field. Our model is based on calculating the transient current density from the time-dependent distribution function which is determined using the Boltzmann transport equation (BTE) within a relaxation time approximation. We include the time-dependent generation of carriers by the pump pulse by solving for the carrier generation rate using the optical Bloch equations in the rotating wave approximation (RWA). The linearly polarized pump pulse generates an anisotropic distribution of photoexcited carriers in the kx-ky plane. The collision integral in the Boltzmann equation includes a term that leads to the thermalization of carriers via carrier-carrier scattering to an effective temperature above the lattice temperature, as well as a cooling term, which leads to energy relaxation via inelastic carrier-phonon scattering. The radiated signal is proportional to the time derivative of the transient current density. In spite of the fact that the magnitude of the velocity is the same for all the carriers in graphene, there is still emitted radiation from the photoexcited charge carriers with frequency components in the THz range due to a change in the direction of velocity of the photoexcited carriers in the external electric field as well as cooling of the photoexcited carriers on a subpicosecond time scale.

Radar RFI at Goldstone DSS 12 and DSS 16

NASA Astrophysics Data System (ADS)

Slobin, S. D.; Peng, T. K.

1990-02-01

Radio frequency interference (RFI) from the DSS 14 Goldstone Solar System Radar (GSSR) was investigated at DSS 12 and DSS 16 with the goal of assisting in the choice of the location of future DSN antennas. Total power measurements at both locations were made at the S-band carrier frequency of 2320 MHz. X-band measurements at the carrier frequency of 8495 MHz could not be made. Exciter-chain output spectrum and klystron output spectrum measurements were made at S- and X-bands using a probable worst-case modulation of the radar signal (short pseudorandom number (PN) code length and short pulse length). Based on these measurements, it is estimated that RFI levels in the DSN receiving bands at both sites (above 10-deg elevation) would be below -192 dBm for a 1-Hz bandwidth

Radar RFI at Goldstone DSS 12 and DSS 16

NASA Technical Reports Server (NTRS)

Slobin, S. D.; Peng, T. K.

1990-01-01

Radio frequency interference (RFI) from the DSS 14 Goldstone Solar System Radar (GSSR) was investigated at DSS 12 and DSS 16 with the goal of assisting in the choice of the location of future DSN antennas. Total power measurements at both locations were made at the S-band carrier frequency of 2320 MHz. X-band measurements at the carrier frequency of 8495 MHz could not be made. Exciter-chain output spectrum and klystron output spectrum measurements were made at S- and X-bands using a probable worst-case modulation of the radar signal (short pseudorandom number (PN) code length and short pulse length). Based on these measurements, it is estimated that RFI levels in the DSN receiving bands at both sites (above 10-deg elevation) would be below -192 dBm for a 1-Hz bandwidth

Charge carrier localization effects on the quantum efficiency and operating temperature range of InAs{sub x}P{sub 1−x}/InP quantum well detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vashisht, Geetanjali, E-mail: geetanjali@rrcat.gov.in; Dixit, V. K., E-mail: dixit@rrcat.gov.in; Porwal, S.

2016-03-07

The effect of charge carrier localization resulting in “S-shaped” temperature dependence of the photoluminescence peak energy of InAs{sub x}P{sub 1−x}/InP quantum wells (QWs) is distinctly revealed by the temperature dependent surface photo voltage (SPV) and photoconductivity (PC) processes. It is observed that the escape efficiency of carriers from QWs depends on the localization energy, where the carriers are unable to contribute in SPV/PC signal below a critical temperature. Below the critical temperature, carriers are strongly trapped in the localized states and are therefore unable to escape from the QW. Further, the critical temperature increases with the magnitude of localization energymore » of carriers. Carrier localization thus plays a pivotal role in defining the operating temperature range of InAs{sub x}P{sub 1−x}/InP QW detectors.« less

Carbon nanotube transistor based high-frequency electronics

NASA Astrophysics Data System (ADS)

Schroter, Michael

At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks.

Transparent megahertz circuits from solution-processed composite thin films.

PubMed

Liu, Xingqiang; Wan, Da; Wu, Yun; Xiao, Xiangheng; Guo, Shishang; Jiang, Changzhong; Li, Jinchai; Chen, Tangsheng; Duan, Xiangfeng; Fan, Zhiyong; Liao, Lei

2016-04-21

Solution-processed amorphous oxide semiconductors have attracted considerable interest in large-area transparent electronics. However, due to its relative low carrier mobility (∼10 cm(2) V(-1) s(-1)), the demonstrated circuit performance has been limited to 800 kHz or less. Herein, we report solution-processed high-speed thin-film transistors (TFTs) and integrated circuits with an operation frequency beyond the megahertz region on 4 inch glass. The TFTs can be fabricated from an amorphous indium gallium zinc oxide/single-walled carbon nanotube (a-IGZO/SWNT) composite thin film with high yield and high carrier mobility of >70 cm(2) V(-1) s(-1). On-chip microwave measurements demonstrate that these TFTs can deliver an unprecedented operation frequency in solution-processed semiconductors, including an extrinsic cut-off frequency (f(T) = 102 MHz) and a maximum oscillation frequency (f(max) = 122 MHz). Ring oscillators further demonstrated an oscillation frequency of 4.13 MHz, for the first time, realizing megahertz circuit operation from solution-processed semiconductors. Our studies represent an important step toward high-speed solution-processed thin film electronics.

Fiber-based polarization-sensitive Mueller matrix optical coherence tomography with continuous source polarization modulation.

PubMed

Jiao, Shuliang; Todorović, Milos; Stoica, George; Wang, Lihong V

2005-09-10

We report on a new configuration of fiber-based polarization-sensitive Mueller matrix optical coherence tomography that permits the acquisition of the round-trip Jones matrix of a biological sample using only one light source and a single depth scan. In this new configuration, a polarization modulator is used in the source arm to continuously modulate the incident polarization state for both the reference and the sample arms. The Jones matrix of the sample can be calculated from the two frequency terms in the two detection channels. The first term is modulated by the carrier frequency, which is determined by the longitudinal scanning mechanism, whereas the other term is modulated by the beat frequency between the carrier frequency and the second harmonic of the modulation frequency of the polarization modulator. One important feature of this system is that, for the first time to our knowledge, the Jones matrix of the sample can be calculated with a single detection channel and a single measurement when diattenuation is negligible. The system was successfully tested by imaging both standard polarization elements and biological samples.

Mirror extreme BMI phenotypes associated with gene dosage at the chromosome 16p11.2 locus

PubMed Central

Jacquemont, Sébastien; Reymond, Alexandre; Zufferey, Flore; Harewood, Louise; Walters, Robin G.; Kutalik, Zoltán; Martinet, Danielle; Shen, Yiping; Valsesia, Armand; Beckmann, Noam D.; Thorleifsson, Gudmar; Belfiore, Marco; Bouquillon, Sonia; Campion, Dominique; De Leeuw, Nicole; De Vries, Bert B. A.; Esko, Tõnu; Fernandez, Bridget A.; Fernández-Aranda, Fernando; Fernández-Real, José Manuel; Gratacòs, Mònica; Guilmatre, Audrey; Hoyer, Juliane; Jarvelin, Marjo-Riitta; Kooy, Frank R.; Kurg, Ants; Le Caignec, Cédric; Männik, Katrin; Platt, Orah S.; Sanlaville, Damien; Van Haelst, Mieke M.; Villatoro Gomez, Sergi; Walha, Faida; Wu, Bai-Lin; Yu, Yongguo; Aboura, Azzedine; Addor, Marie-Claude; Alembik, Yves; Antonarakis, Stylianos E.; Arveiler, Benoît; Barth, Magalie; Bednarek, Nathalie; Béna, Frédérique; Bergmann, Sven; Beri, Mylène; Bernardini, Laura; Blaumeiser, Bettina; Bonneau, Dominique; Bottani, Armand; Boute, Odile; Brunner, Han G.; Cailley, Dorothée; Callier, Patrick; Chiesa, Jean; Chrast, Jacqueline; Coin, Lachlan; Coutton, Charles; Cuisset, Jean-Marie; Cuvellier, Jean-Christophe; David, Albert; De Freminville, Bénédicte; Delobel, Bruno; Delrue, Marie-Ange; Demeer, Bénédicte; Descamps, Dominique; Didelot, Gérard; Dieterich, Klaus; Disciglio, Vittoria; Doco-Fenzy, Martine; Drunat, Séverine; Duban-Bedu, Bénédicte; Dubourg, Christèle; El-Sayed Moustafa, Julia S.; Elliott, Paul; Faas, Brigitte H. W.; Faivre, Laurence; Faudet, Anne; Fellmann, Florence; Ferrarini, Alessandra; Fisher, Richard; Flori, Elisabeth; Forer, Lukas; Gaillard, Dominique; Gerard, Marion; Gieger, Christian; Gimelli, Stefania; Gimelli, Giorgio; Grabe, Hans J.; Guichet, Agnès; Guillin, Olivier; Hartikainen, Anna-Liisa; Heron, Délphine; Hippolyte, Loyse; Holder, Muriel; Homuth, Georg; Isidor, Bertrand; Jaillard, Sylvie; Jaros, Zdenek; Jiménez-Murcia, Susana; Joly Helas, Géraldine; Jonveaux, Philippe; Kaksonen, Satu; Keren, Boris; Kloss-Brandstätter, Anita; Knoers, Nine V. A. M.; Koolen, David A.; Kroisel, Peter M.; Kronenberg, Florian; Labalme, Audrey; Landais, Emilie; Lapi, Elisabetta; Layet, Valérie; Legallic, Solenn; Leheup, Bruno; Leube, Barbara; Lewis, Suzanne; Lucas, Josette; Macdermot, Kay D.; Magnusson, Pall; Marshall, Christian R.; Mathieu-Dramard, Michèle; Mccarthy, Mark I.; Meitinger, Thomas; Antonietta Mencarelli, Maria; Merla, Giuseppe; Moerman, Alexandre; Mooser, Vincent; Morice-Picard, Fanny; Mucciolo, Mafalda; Nauck, Matthias; Coumba Ndiaye, Ndeye; Nordgren, Ann; Pasquier, Laurent; Petit, Florence; Pfundt, Rolph; Plessis, Ghislaine; Rajcan-Separovic, Evica; Paolo Ramelli, Gian; Rauch, Anita; Ravazzolo, Roberto; Reis, Andre; Renieri, Alessandra; Richart, Cristobal; Ried, Janina S.; Rieubland, Claudine; Roberts, Wendy; Roetzer, Katharina M.; Rooryck, Caroline; Rossi, Massimiliano; Saemundsen, Evald; Satre, Véronique; Schurmann, Claudia; Sigurdsson, Engilbert; Stavropoulos, Dimitri J.; Stefansson, Hreinn; Tengström, Carola; Thorsteinsdóttir, Unnur; Tinahones, Francisco J.; Touraine, Renaud; Vallée, Louis; Van Binsbergen, Ellen; Van Der Aa, Nathalie; Vincent-Delorme, Catherine; Visvikis-Siest, Sophie; Vollenweider, Peter; Völzke, Henry; Vulto-Van Silfhout, Anneke T.; Waeber, Gérard; Wallgren-Pettersson, Carina; Witwicki, Robert M.; Zwolinksi, Simon; Andrieux, Joris; Estivill, Xavier; Gusella, James F.; Gustafsson, Omar; Metspalu, Andres; Scherer, Stephen W.; Stefansson, Kari; Blakemore, Alexandra I. F.; Beckmann, Jacques S.; Froguel, Philippe

2011-01-01

Both underweight and obesity have been associated with increased mortality1,2. Underweight, defined as body mass index (BMI) ≤ 18,5 kg/m2 in adults 3 and ≤ −2 standard deviations (SD) in children4,5, is the main sign of a series of heterogeneous clinical conditions such as failure to thrive (FTT) 6–8, feeding and eating disorder and/or anorexia nervosa9,10. In contrast to obesity, few genetic variants underlying these clinical conditions have been reported 11, 12. We previously demonstrated that hemizygosity of a ~600 kb region on the short arm of chromosome 16 (chr16:29.5–30.1Mb), causes a highly-penetrant form of obesity often associated with hyperphagia and intellectual disabilities13. Here we show that the corresponding reciprocal duplication is associated with underweight. We identified 138 (132 novel cases) duplication carriers (108 unrelated carriers) from over 95,000 individuals clinically-referred for developmental or intellectual disabilities (DD/ID), psychiatric disorders or recruited from population-based cohorts. These carriers show significantly reduced postnatal weight (mean Z-score −0.6; p=4.4×10−4) and BMI (mean Z-score −0.5; p=2.0×10−3). In particular, half of the boys younger than 5 years are underweight with a probable diagnosis of FTT, while adult duplication carriers have an 8.7-fold (p=5.9×10−11; CI_95=[4.5–16.6]) increased risk of being clinically underweight. We observe a significant trend towards increased severity in males, as well as a depletion of male carriers among non-medically ascertained cases. These features are associated with an unusually high frequency of selective and restrictive feeding behaviours and a significant reduction in head circumference (mean Z-score −0.9; p=7.8×10−6). Each of the observed phenotypes is the converse of one reported in carriers of deletions at this locus, correlating with changes in transcript levels for genes mapping within the duplication but not within flanking regions. The reciprocal impact of these 16p11.2 copy number variants suggests that severe obesity and being underweight can have mirror etiologies, possibly through contrasting effects on eating behaviour. PMID:21881559

Recurrent TP53 missense mutation in cancer patients of Arab descent.

PubMed

Zick, Aviad; Kadouri, Luna; Cohen, Sherri; Frohlinger, Michael; Hamburger, Tamar; Zvi, Naama; Plaser, Morasha; Avital, Eilat; Breuier, Shani; Elian, Firase; Salah, Azzam; Goldberg, Yael; Peretz, Tamar

2017-04-01

Hereditary cancer comprises more than 10% of all breast cancer cases. Identification of germinal mutations enables the initiation of a preventive program that can include early detection or preventive treatment and may also have a major impact on cancer therapy. Several recurrent mutations were identified in the BRCA1/2 genes in Jewish populations however, in other ethnic groups in Israel, no recurrent mutations were identified to date. Our group established panel sequencing in cancer patients to identify recurrent, founder, and new mutations in the heterogeneous and diverse populations in Israel, We evaluated five breast cancer patients of Arab descent diagnosed with cancer before the age of 50 years and identified the previously described TP53 mutation, c.541C>T, R181C (rs587782596), in two women from unrelated Arab families. The two probands were diagnosed with breast cancer at a young age (27 and 34 years) and had significant family history spanning a wide range of tumors (breast cancer (BC), papillary thyroid cancer, glioblastoma multiform (GBM), colon cancer and leukemia). The R181C variant is expected to disrupt p53 at the ASPP2 binding domain but not the DNA binding domain and is defined by Clinvar as likely pathogenic and in HGMD as disease mutation. We further tested 85 unrelated Arab cancer patients and father of a BC carrier patient for TP53 c.541C>T using a real time polymerase chain reaction (RT-PCR) approach and identified four additional carriers, two with BC one with lung cancer, and the father of a BC carrier patient, diagnosed with GBM. Another carrier suffering from BC was identified using a Myriad panel, suggesting a recurrent mutation in this population with a frequency of 5/42 (11.9%) of our selected BC patients. We suggest testing Arab women with a breast cancer at a young age, Arab patients with multiple malignancies, or with suggestive family history for TP53 c.541C>T.

78 FR 21121 - Information Collection(s) Being Reviewed by the Federal Communications Commission, Comments...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-09

... the carrier frequency, output power, and modulation of each transmitter authorized to operate with... per Response: .033 hours. Frequency of Response: Recordkeeping requirement. Obligation to Respond... which would likely affect the modulation characteristics. Such measurements, which help ensure proper...

Preproghrelin Leu72Met polymorphism predicts a lower rate of developing renal dysfunction in type 2 diabetic nephropathy.

PubMed

Lee, Dae-Yeol; Kim, Sun-Young; Jo, Dae-Sun; Hwang, Pyoung Han; Kang, Kyung Pyo; Lee, Sik; Kim, Won; Park, Sung Kwang

2006-07-01

Ghrelin is a novel peptide hormone, which exerts somatotropic, orexigenic and adipogenic effects. Recent studies have shown that the preproghrelin Leu72Met polymorphism is associated with serum creatinine (Scr) concentration in type 2 diabetes; 72Met carriers exhibited lower Scr levels as compared with the 72Met non-carriers. We hypothesized that the preproghrelin Leu72Met polymorphism is associated with a lower rate of developing renal dysfunction in patients with type 2 diabetic nephropathy. The preproghrelin Leu72Met polymorphism was investigated using PCR techniques in 138 patients with diabetic nephropathy divided into two groups, one with normal renal function and the other with renal dysfunction. Determination of the frequency of the preproghrelin Leu72Met polymorphism was the main outcome measure. The frequency of the Leu72Met polymorphism in diabetic nephropathy was significantly lower in patients with renal dysfunction (15.9%, P < 0.01) than in patients with normal renal function (42.0%) or in the diabetes control group (40.6%). The Leu72Met polymorphism was also associated with serum total cholesterol levels in diabetic nephropathy patients with renal dysfunction; the 72Met carriers had lower total cholesterol levels than the 72Met non-carriers (P < 0.05). These data suggest that 72Met carrier status may be used as a marker predicting a lower chance of developing renal dysfunction in diabetic nephropathy.

The Hazard of Exposure to Impulse Noise as a Function of Frequency. Volume 2

DTIC Science & Technology

1991-06-01

H. Patterson, Jr. Melvin Carrier, Jr. Kevin Bordwell Ilia M. Lomba Gautier Sensory Research Division DTIC and f’:EL EC T . Roger P. Hamernik 16 19g1...Melvin Carrier, Jr., Kevin Bordwell , Ilia M. Lomba Gautier, Roger P. Hamernik, William A. Ahroon, George Turrentine, and C. E. Hargett, Jr. 13a. TYPE

Flattened optical frequency-locked multi-carrier generation by cascading one EML and one phase modulator driven by different RF clocks

NASA Astrophysics Data System (ADS)

Li, Xinying; Xiao, Jiangnan

2015-06-01

We propose a novel scheme for optical frequency-locked multi-carrier generation based on one electro-absorption modulated laser (EML) and one phase modulator (PM) in cascade driven by different sinusoidal radio-frequency (RF) clocks. The optimal operating zone for the cascaded EML and PM is found out based on theoretical analysis and numerical simulation. We experimentally demonstrate 25 optical subcarriers with frequency spacing of 12.5 GHz and power difference less than 5 dB can be generated based on the cascaded EML and PM operating in the optimal zone, which agrees well with the numerical simulation. We also experimentally demonstrate 28-Gbaud polarization division multiplexing quadrature phase shift keying (PDM-QPSK) modulated coherent optical transmission based on the cascaded EML and PM. The bit error ratio (BER) can be below the pre-forward-error-correction (pre-FEC) threshold of 3.8 × 10-3 after 80-km single-mode fiber-28 (SMF-28) transmission.

Dual-function photonic integrated circuit for frequency octo-tupling or single-side-band modulation.

PubMed

Hasan, Mehedi; Maldonado-Basilio, Ramón; Hall, Trevor J

2015-06-01

A dual-function photonic integrated circuit for microwave photonic applications is proposed. The circuit consists of four linear electro-optic phase modulators connected optically in parallel within a generalized Mach-Zehnder interferometer architecture. The photonic circuit is arranged to have two separate output ports. A first port provides frequency up-conversion of a microwave signal from the electrical to the optical domain; equivalently single-side-band modulation. A second port provides tunable millimeter wave carriers by frequency octo-tupling of an appropriate amplitude RF carrier. The circuit exploits the intrinsic relative phases between the ports of multi-mode interference couplers to provide substantially all the static optical phases needed. The operation of the proposed dual-function photonic integrated circuit is verified by computer simulations. The performance of the frequency octo-tupling and up-conversion functions is analyzed in terms of the electrical signal to harmonic distortion ratio and the optical single side band to unwanted harmonics ratio, respectively.

Vibro-Acoustic Modulation Based Damage Identification in a Composite Skin-Stiffener Structure

NASA Technical Reports Server (NTRS)

Ooijevaar, T. H.; Loendersloot, R.; Rogge, M. D.; Akkerman, R.; Tinga, T.

2014-01-01

The vibro-acoustic modulation method is applied to a composite skin-stiffener structure to investigate the possibilities to utilize this method for damage identification in terms of detection, localisation and damage quantification. The research comprises a theoretical part and an experimental part. An impact load is applied to the skin-stiffener structure, resulting in a delamination underneath the stiffener. The structure is interrogated with a low frequency pump excitation and a high frequency carrier excitation. The analysis of the response in a frequency band around the carrier frequency is employed to assess the damage identification capabilities and to gain a better understanding of the modulations occurring and the underlying physical phenomena. Though vibro-acoustic is shown to be a sensitive method for damage identification, the complexity of the damage, combined with a high modal density, complicate the understanding of the relation between the physical phenomena and the modulations occurring. more research is recommended to reveal the physics behind the observations.

Linear modulator

NASA Technical Reports Server (NTRS)

1972-01-01

A study of frequency division multiplexing (FDM) systems was made for the purpose of determining the system performance that can be obtained with available state of the art components. System performance was evaluated on the basis of past experience, system analysis, and component evaluation. The system study was specifically directed to the area of FDM systems using subcarrier channel frequencies from 4 kHz to 200 kHz and channel information bandwidths of dc to 1, 2, 4, 8, and 16 kHz. The evaluation also assumes that the demodulation will be from a tape recorder which produces frequency modulation of + or - 1% on the signal due to the tape recorder wow and flutter. For the modulation system it is assumed that the pilot and carrier channel frequencies are stable to within + or - .005% and that the FM on the channel carriers is negligible. The modulator system was evaluated for the temperature range of -20 degree to +85 degree while the demodulator system was evaluated for operation at room temperature.

Special Semaphore Scheme for UHF Spacecraft Communications

NASA Technical Reports Server (NTRS)

Butman, Stanley; Satorius, Edgar; Ilott, Peter

2006-01-01

A semaphore scheme has been devised to satisfy a requirement to enable ultrahigh- frequency (UHF) radio communication between a spacecraft descending from orbit to a landing on Mars and a spacecraft, in orbit about Mars, that relays communications between Earth and the lander spacecraft. There are also two subsidiary requirements: (1) to use UHF transceivers, built and qualified for operation aboard the spacecraft that operate with residual-carrier binary phase-shift-keying (BPSK) modulation at a selectable data rate of 8, 32, 128, or 256 kb/s; and (2) to enable low-rate signaling even when received signals become so weak as to prevent communication at the minimum BPSK rate of 8 kHz. The scheme involves exploitation of Manchester encoding, which is used in conjunction with residual-carrier modulation to aid the carrier-tracking loop. By choosing various sequences of 1s, 0s, or 1s alternating with 0s to be fed to the residual-carrier modulator, one would cause the modulator to generate sidebands at a fundamental frequency of 4 or 8 kHz and harmonics thereof. These sidebands would constitute the desired semaphores. In reception, the semaphores would be detected by a software demodulator.

Measurement of a free spectral range of a Fabry-Perot cavity using frequency modulation and null method under off-resonance conditions

NASA Astrophysics Data System (ADS)

Aketagawa, Masato; Kimura, Shohei; Yashiki, Takuya; Iwata, Hiroshi; Banh, Tuan Quoc; Hirata, Kenji

2011-02-01

In this paper, we discuss a method to measure the free spectral range (FSR) of a Fabry-Perot cavity (FP-cavity) using frequency modulation with one electric optical modulator (EOM) and the null method. A laser beam modulated by the EOM, to which a sine wave signal is supplied from a radio frequency (RF) oscillator, is incident on the FP-cavity. The transmitted or reflected light from the FP-cavity is observed and converted to an RF signal by a high-speed photodetector, and the RF signal is synchronously demodulated with a lock-in amplifier by referring to a cosine wave signal from the oscillator. We theoretically and experimentally demonstrate that the lock-in amplifier signal for the transmitted or reflected light becomes null with a steep slope when the modulation frequency is equal to the FSR under the condition that the carrier frequency of the laser is slightly detuned from the resonance of the FP-cavity. To reduce the measurement uncertainty for the FSR, we also discuss a selection method for laser power, a modulation index and the detuning shift of the carrier frequency, respectively.

Low noise erbium fiber fs frequency comb based on a tapered-fiber carbon nanotube design.

PubMed

Wu, Tsung-Han; Kieu, K; Peyghambarian, N; Jones, R J

2011-03-14

We report on a low noise all-fiber erbium fs frequency comb based on a simple and robust tapered-fiber carbon nanotube (tf-CNT) design. We mitigate dominant noise sources to show that the free-running linewidth of the carrier-envelope offset frequency (fceo) can be comparable to the best reported performance to date for fiber-based frequency combs. A free-running fceo linewidth of ~20 kHz is demonstrated, corresponding to an improvement of ~30 times over previous work based on a CNT mode-locked fiber laser [Opt. Express 18, 1667 (2010)]. We also demonstrate the use of an acousto-optic modulator external to the laser cavity to stabilize fceo, enabling a 300 kHz feedback control bandwidth. The offset frequency is phase-locked with an in-loop integrated phase noise of ~0.8 rad from 10Hz to 400kHz. We show a resolution-limited linewidth of ~1 Hz, demonstrating over 90% of the carrier power within the coherent fceo signal. The results demonstrate that the relatively simple tf-CNT fiber laser design can provide a compact, robust and high-performance fs frequency comb.

The high frequency of GJB2 gene mutation c.313_326del14 suggests its possible origin in ancestors of Lithuanian population.

PubMed

Mikstiene, Violeta; Jakaitiene, Audrone; Byckova, Jekaterina; Gradauskiene, Egle; Preiksaitiene, Egle; Burnyte, Birute; Tumiene, Birute; Matuleviciene, Ausra; Ambrozaityte, Laima; Uktveryte, Ingrida; Domarkiene, Ingrida; Rancelis, Tautvydas; Cimbalistiene, Loreta; Lesinskas, Eugenijus; Kucinskas, Vaidutis; Utkus, Algirdas

2016-02-19

Congenital hearing loss (CHL) is diagnosed in 1 - 2 newborns in 1000, genetic factors contribute to two thirds of CHL cases in industrialised countries. Mutations of the GJB2 gene located in the DFNB1 locus (13q11-12) are a major cause of CHL worldwide. The aim of this cross-sectional study was to assess the contribution of the DFNB1 locus containing the GJB2 and GJB6 genes in the development of early onset hearing loss in the affected group of participants, to determine the population-specific mutational profile and DFNB1-related HL burden in Lithuanian population. Clinical data were obtained from a collection of 158 affected participants (146 unrelated probands) with early onset non-syndromic HL. GJB2 and GJB6 gene sequencing and GJB6 gene deletion testing were performed. The data of GJB2 and GJB6 gene sequencing in 98 participants in group of self-reported healthy Lithuanian inhabitants were analysed. Statistic summary, homogeneity tests, and logistic regression analysis were used for the assessment of genotype-phenotype correlation. Our findings show 57.5% of affected participants with two pathogenic GJB2 gene mutations identified. The most prevalent GJB2 mutations were c.35delG, p. (Gly12Valfs*2) (rs80338939) and c.313_326del14, p. (Lys105Glyfs*5) (rs111033253) with allele frequencies 64.7% and 28.3% respectively. GJB6 gene mutations were not identified in the affected group of participants. The statistical analysis revealed significant differences between GJB2(-) and GJB2(+) groups in disease severity (p = 0.001), and family history (p = 0.01). The probability of identification of GJB2 mutations in patients with various HL characteristics was estimated. The carrier rate of GJB2 gene mutations - 7.1% (~1 in 14) was identified in the group of healthy participants and a high frequency of GJB2-related hearing loss was estimated in our population. The results show a very high proportion of GJB2-positive individuals in the research group affected with sensorineural HL. The allele frequency of c.35delG mutation (64.7 %) is consistent with many previously published studies in groups of affected individuals of Caucasian populations. The high frequency of the c.313_326del14 (28.3 % of pathogenic alleles) mutation in affected group of participants was an unexpected finding in our study suggesting not only a high frequency of carriers of this mutation in our population but also its possible origin in Lithuanian ancestors. The high frequency of carriers of the c.313_326del14 mutation in the entire Lithuanian population is supported by it being identified twice in the ethnic Lithuanian group of healthy participants (a frequency 2.0 % of carriers in the study group). Analysis of the allele frequency of GJB2 gene mutations revealed a high proportion of c. 313_326del14 (rs111033253) mutations in the GJB2-positive group suggesting its possible origin in Lithuanian forebears. The high frequency of carriers of GJB2 gene mutations in the group of healthy participants corresponds to the substantial frequency of GJB2-associated HL in Lithuania. The observations of the study indicate the significant contribution of GJB2 gene mutations to the pathogenesis of the disorder in the Lithuanian population and will contribute to introducing principles to predict the characteristics of the disease in patients.

Determine the optimal carrier selection for a logistics network based on multi-commodity reliability criterion

NASA Astrophysics Data System (ADS)

Lin, Yi-Kuei; Yeh, Cheng-Ta

2013-05-01

From the perspective of supply chain management, the selected carrier plays an important role in freight delivery. This article proposes a new criterion of multi-commodity reliability and optimises the carrier selection based on such a criterion for logistics networks with routes and nodes, over which multiple commodities are delivered. Carrier selection concerns the selection of exactly one carrier to deliver freight on each route. The capacity of each carrier has several available values associated with a probability distribution, since some of a carrier's capacity may be reserved for various orders. Therefore, the logistics network, given any carrier selection, is a multi-commodity multi-state logistics network. Multi-commodity reliability is defined as a probability that the logistics network can satisfy a customer's demand for various commodities, and is a performance indicator for freight delivery. To solve this problem, this study proposes an optimisation algorithm that integrates genetic algorithm, minimal paths and Recursive Sum of Disjoint Products. A practical example in which multi-sized LCD monitors are delivered from China to Germany is considered to illustrate the solution procedure.

The ABCA4 2588G>C Stargardt mutation: single origin and increasing frequency from South-West to North-East Europe.

PubMed

Maugeri, Alessandra; Flothmann, Kris; Hemmrich, Nadine; Ingvast, Sofie; Jorge, Paula; Paloma, Eva; Patel, Reshma; Rozet, Jean-Michel; Tammur, Jaana; Testa, Francesco; Balcells, Susana; Bird, Alan C; Brunner, Han G; Hoyng, Carel B; Metspalu, Andres; Simonelli, Francesca; Allikmets, Rando; Bhattacharya, Shomi S; D'Urso, Michele; Gonzàlez-Duarte, Roser; Kaplan, Josseline; te Meerman, Gerard J; Santos, Rosário; Schwartz, Marianne; Van Camp, Guy; Wadelius, Claes; Weber, Bernhard H F; Cremers, Frans P M

2002-03-01

Inherited retinal dystrophies represent the most important cause of vision impairment in adolescence, affecting approximately 1 out of 3000 individuals. Mutations of the photoreceptor-specific gene ABCA4 (ABCR) are a common cause of retinal dystrophy. A number of mutations have been repeatedly reported for this gene, notably the 2588G>C mutation which is frequent in both patients and controls. Here we ascertained the frequency of the 2588G>C mutation in a total of 2343 unrelated random control individuals from 11 European countries and 241 control individuals from the US, as well as in 614 patients with STGD both from Europe and the US. We found an overall carrier frequency of 1 out of 54 in Europe, compared with 1 out of 121 in the US, confirming that the 2588G>C ABCA4 mutation is one of the most frequent autosomal recessive mutations in the European population. Carrier frequencies show an increasing gradient in Europe from South-West to North-East. The lowest carrier frequency, 0 out of 199 (0%), was found in Portugal; the highest, 11 out of 197 (5.5%), was found in Sweden. Haplotype analysis in 16 families segregating the 2588G>C mutation showed four intragenic polymorphisms invariably present in all 16 disease chromosomes and sharing of the same allele for several markers flanking the ABCA4 locus in most of the disease chromosomes. These results indicate a single origin of the 2588G>C mutation which, to our best estimate, occurred between 2400 and 3000 years ago.

Observation of frequency up-conversion in the propagation of a high-power microwave pulse in a self-generated plasma

NASA Technical Reports Server (NTRS)

Kuo, S. P.; Zhang, Y. S.; Ren, A.

1990-01-01

A chamber experiment is conducted to study the propagation of a high-power microwave pulse. The results show that the pulse is experiencing frequency up-shift while ionizing the background air if the initial carrier frequency of the pulse is higher than the electron plasma frequency at the incident boundary. Such a frequency autoconversion process may lead to reflectionless propagation of a high-power microwave pulse through the atmosphere.