Faculty Opinions recommendation of Multiscale mapping of frequency sweep rate in mouse auditory cortex.

This paper presents a frequency-modulated optical signal generator in the THz band. The proposed method is based on a fast optical frequency sweep of a single narrowband laser diode used together with an optical fiber interferometer. The optical frequency sweep using a single laser diode is achieved by generating short current pulses with a high amplitude, which are driving the laser diode. Theoretical analysis showed that the modulation frequency could be changed by the optical path difference of the interferometer or optical frequency sweep rate of a laser diode. The efficiency of the optical signal generator with Michelson and Fabry–Perot interferometers is theoretically analyzed and experimentally evaluated for three different scenarios. Interferometers with different optical path differences and a fixed optical frequency sweep rate were used in the first scenario. Different optical frequency sweep rates and fixed optical path differences of the interferometers were used in the second scenario. This paper presents a method for optical chirp generation using a programmable current pulse waveform, which drives a laser diode to achieve nonlinear optical sweep with a fixed optical path difference of the interferometer. The experimental results showed that the proposed signals could be generated within a microwave (1–30 GHz) and THz band (0.1–0.3 THz).

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Sei whale localization and vocalization frequency sweep rate estimation during the New Jersey Shallow Water 2006 experiment.

The Journal of the Acoustical Society of America ◽

10.1121/1.4784544 ◽

2009 ◽

Vol 125 (4) ◽

pp. 2738-2738 ◽

Cited By ~ 2

Author(s):

Arthur E. Newhall ◽

Ying‐Tsong Lin ◽

James F. Lynch ◽

Mark F. Baumgartner

Keyword(s):

New Jersey ◽

Shallow Water ◽

Sweep Rate ◽

Frequency Sweep ◽

Rate Estimation

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Frequency sweep rate dependence on the dielectrophoretic response of polystyrene beads and red blood cells

Biomicrofluidics ◽

10.1063/1.4833095 ◽

2013 ◽

Vol 7 (6) ◽

pp. 064114 ◽

Cited By ~ 13

Author(s):

T. N. G. Adams ◽

K. M. Leonard ◽

A. R. Minerick

Keyword(s):

Red Blood Cells ◽

Blood Cells ◽

Sweep Rate ◽

Rate Dependence ◽

Frequency Sweep ◽

Polystyrene Beads

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Neural Mechanisms Underlying Selectivity for the Rate and Direction of Frequency-Modulated Sweeps in the Auditory Cortex of the Pallid Bat

Journal of Neurophysiology ◽

10.1152/jn.00020.2006 ◽

2006 ◽

Vol 96 (3) ◽

pp. 1303-1319 ◽

Cited By ~ 69

Author(s):

Khaleel A. Razak ◽

Zoltan M. Fuzessery

Keyword(s):

Auditory Cortex ◽

High Frequency ◽

Cortical Neurons ◽

Arrival Time ◽

Narrow Band ◽

Low Frequency ◽

Sweep Rate ◽

Direction Selectivity ◽

Pallid Bats ◽

Pallid Bat

Frequency-modulated (FM) sweeps are common in vocalizations, including human speech. Selectivity for FM sweep rate and direction is present in the auditory cortex of many species. The present study sought to determine the mechanisms underlying FM sweep selectivity in the auditory cortex of pallid bats. In the pallid bat inferior colliculus (IC), two mechanisms underlie selectivity for FM sweep rate. The first mechanism depends on duration tuning for tones that arises as a consequence of early inhibition generated by an excitatory tone. The second mechanism depends on a narrow band of delayed high-frequency inhibition. Direction selectivity depends on a broad band of early low-frequency inhibition. Here, the contributions of these mechanisms to cortical FM sweep selectivity were determined in pentobarbital-anesthetized pallid bats. We show that the majority of cortical neurons tuned to echolocation frequencies are selective for the downward direction and rate of FM sweeps. Unlike in IC neurons tuned in the echolocation range, duration tuning is rare in cortical neurons with similar tuning. As in the IC, consistent spectrotemporal differences exist between low- and high-frequency sidebands. A narrow band of delayed high-frequency inhibition is necessary for FM rate selectivity. Low-frequency inhibition has a broad bandwidth, early arrival time, and creates direction selectivity. Cortical neurons respond better to slower FM rates and exhibit broader rate tuning than IC neurons. Relative arrival time of high-frequency inhibition is slower in the cortex than in the IC. Thus whereas similar mechanisms shape direction selectivity of neurons tuned in the echolocation range in the IC and the cortex, only one of the two mechanisms underlying rate selectivity in the IC is present in the cortex.

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On the Frequency Sweep Rate Estimation in Airborne FMCW SAR Systems

Remote Sensing ◽

10.3390/rs12203448 ◽

2020 ◽

Vol 12 (20) ◽

pp. 3448

Author(s):

Carmen Esposito ◽

Paolo Berardino ◽

Antonio Natale ◽

Stefano Perna

Keyword(s):

Synthetic Aperture Radar ◽

Experimental Analysis ◽

Continuous Wave ◽

Sweep Rate ◽

Accurate Estimate ◽

Synthetic Aperture ◽

Time Interval ◽

Sar Image ◽

Frequency Sweep ◽

Electronic Parameters

Use of Frequency Modulated Continuous Wave (FMCW) Synthetic Aperture Radar (SAR) systems requires to accurately know the electronic parameters of the system. In particular, the use of an incorrect value of the Frequency Sweep Rate (FSR) introduces geometric distortions in the focused images. Recently, a method, that we name FSR Estimate Through Corner reflectors (FSRETC), has been proposed to estimate the FSR value actually employed by the radar. The method is based on the use of the SAR image focused with the available erroneous FSR. Moreover, it exploits a number of Corner Reflectors (CRs) deployed over the illuminated area. In this work, we provide an assessment of the capabilities of the FSRETC algorithm. The overall analysis is performed through the use of a real dataset consisting of 10 acquisitions carried out in 2018 (5 acquisitions) and 2019 (5 acquisitions) with an airborne FMCW SAR system. The presented experimental analysis shows that even with a single acquisition, use of two CRs sufficiently far from each other in the range direction, allows achieving an accurate estimate of the searched FSR. Moreover, it is shown that the obtained estimate is very stable over the time. Therefore, the overall procedure can be applied only once, since the estimated values can be safely used for the subsequent missions, at least for the time interval considered in the work, that is, 14 months. In addition, the presented results pose the basis for an enhanced measurement strategy that allows effective application of the FSRETC algorithm through the use of only one CR.

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Verification of the backward wave oscillator model of VLF chorus generation using data from MAGION 5 satellite

Annales Geophysicae ◽

10.5194/angeo-21-1073-2003 ◽

2003 ◽

Vol 21 (5) ◽

pp. 1073-1081 ◽

Cited By ~ 33

Author(s):

E. E. Titova ◽

B. V. Kozelov ◽

F. Jiriček ◽

J. Smilauer ◽

A. G. Demekhov ◽

...

Keyword(s):

Space Plasma ◽

Sweep Rate ◽

Particle Interactions ◽

Space Plasma Physics ◽

Frequency Sweep ◽

Backward Wave Oscillator ◽

Wave Oscillator ◽

Backward Wave ◽

Using Data ◽

Vlf Emissions

Abstract. We present a detailed study of chorus emissions in the magnetosphere detected on board Magion 5, when the satellite was not far from the magnetic equator. We determine the frequency sweep rate of more than 8500 electromagnetic VLF chorus elements. These results are compared with the backward wave oscillator (BWO) regime of chorus generation. Comparison of the frequency sweep rate with the BWO model shows: (i) There is a correlation between the frequency sweep rates and the chorus amplitudes. The frequency sweep rate increases with chorus amplitude, in accordance with expectations from the BWO model; (ii) The chorus growth rate, estimated from the frequency sweep rate, is in accord with that inferred from the BWO generation mechanism; (iii) The BWO regime of chorus generation ensures the observed decrease in the frequency sweep rate of the chorus elements with increasing L-shell.Key words. Magnetospheric physics (VLF emissions, energetic particles) – Space plasma physics (wave-particle interactions)

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