Rain parameter estimation using impact generated low‐frequency acoustic signals

2003 ◽  
Vol 113 (4) ◽  
pp. 2278-2278
Author(s):  
T. K. Mani ◽  
P. R. Saseendran Pillai ◽  
James Kurian ◽  
Supriya M. Hariharan
Keyword(s):  
Parameter Estimation ◽  
Low Frequency ◽  
Acoustic Signals

Fish Attraction with Pulsed Low-Frequency Sound

1968 ◽  
Vol 25 (7) ◽  
pp. 1441-1452 ◽  
Author(s):  
Joseph D. Richard
Keyword(s):  
Acoustic Stimulus ◽  
Low Frequency ◽  
Reef Fishes ◽  
Test Site ◽  
Acoustic Signals ◽  
Commercial Fisheries ◽  
Test Results ◽  
Potential Applications ◽  
Predatory Fishes ◽  
Underwater Television

A series of tests were conducted to determine the effectiveness of pulsed low-frequency acoustic signals for attracting fishes. The acoustic signals were contrived to simulate the hydrodynamically generated disturbances normally associated with active predation. Underwater television was used to observe fish arrivals during both control and test periods. Demersal predatory fishes were successfully attracted although they habituated rapidly to the acoustic stimulus. Members of the families Serranidae, Lutjanidae, and Pomadasyidae were particularly well represented among the fishes attracted. Sharks were also attracted in considerable numbers. Herbivorous reef fishes, although common around the test site, were not attracted. Possible relationships between the test results and the hearing capabilities of fishes are discussed. It is concluded that acoustic attraction techniques have potential applications in certain existing commercial fisheries.

Coherence of low‐frequency acoustic signals in the deep ocean

1974 ◽  
Vol 56 (4) ◽  
pp. 1122-1125 ◽  
Author(s):  
J. D. Shaffer ◽  
R. M. Fitzgerald ◽  
A. N. Guthrie
Keyword(s):  
Low Frequency ◽  
Deep Ocean ◽  
Acoustic Signals

scholarly journals Study of low frequency acoustic signals from superheated droplet detector

2013 ◽  
Vol 729 ◽  
pp. 182-187 ◽  
Author(s):  
Prasanna Kumar Mondal ◽  
Susnata Seth ◽  
Mala Das ◽  
Pijushpani Bhattacharjee
Keyword(s):  
Low Frequency ◽  
Acoustic Signals

"Smooth" Rhythms as Probes of Entrainment

1993 ◽  
Vol 10 (4) ◽  
pp. 503-508 ◽  
Author(s):  
Robert O. Gjerdingen
Keyword(s):  
Frequency Domain ◽  
Amplitude Modulation ◽  
Acoustic Signal ◽  
Low Frequency ◽  
Digital Filtering ◽  
Acoustic Signals ◽  
Frequency Range ◽  
Carrier Wave ◽  
The Brain

If one hypothesizes rhythmic perception as a process employing oscillatory circuits in the brain that entrain to low-frequency periodicities in the neural firings evoked by an acoustic signal, then among the conceptually purest probes of those oscillatory circuits would be acoustic signals with only simple sinusoidal periodicities in the appropriate frequency range (perhaps from 0.3 Hz to 20 Hz). Such signals can be produced by the low- frequency amplitude modulation of an audible carrier wave by one or more sinusoids. The resulting rhythms are "smooth" in that their amplitude envelopes are smoothly varying with no obvious points of onset or offset. Because preliminary experiments with smooth rhythms have produced some unexpected results, and because smooth rhythms can be precisely controlled and varied (including, for example, the digital filtering of their Fourier components in the frequency domain), they are proposed as versatile stimuli for studies in rhythmic perception.

Parameter Estimation of Low-Frequency Signal with Negative Frequency Contribution

2013 ◽  
Vol 380-384 ◽  
pp. 3457-3460 ◽  
Author(s):  
Si Wei Tan ◽  
Zhi Liang Ren ◽  
Jiong Sun
Keyword(s):  
Parameter Estimation ◽  
Phase Difference ◽  
Spectrum Analysis ◽  
Low Frequency ◽  
High Accuracy ◽  
Signal Parameter ◽  
Frequency Signal ◽  
Spectrum Method ◽  
Analysis Theory ◽  
Simulation Results

According to the problem that there is a decline in accuracy of low-frequency signal parameter estimation by using the algorithm of all-phase FFT, an improved phase difference correcting spectrum method based on all-phase FFT is proposed. The contribution of negative frequency to FFT calculation was considered while using phase difference correcting spectrum method. The all-phase FFT spectrum analysis theory was presented as well as a traditional phase difference correcting method based on it. The equations of parameter estimation such as frequency, amplitude and phase for low-frequency signals were derived with the negative frequency contribution to spectrum analysis. The simulation results show that the method proposed in this paper can be used to estimate the parameters of low-frequency signals in a high accuracy, and also achieves an improvement in anti-noise ability.

Visualizing detecting low-frequency underwater acoustic signals by means of optical diffraction

2016 ◽  
Vol 55 (8) ◽  
pp. 2018 ◽  
Author(s):  
Yao Ren ◽  
Runcai Miao ◽  
Xiaoming Su ◽  
Hua Chen
Keyword(s):  
Low Frequency ◽  
Acoustic Signals ◽  
Optical Diffraction ◽  
Underwater Acoustic

scholarly journals EXPERIMENTAL STUDIES OF THE DISTRIBUTION OF VARIOUS SPECIES OF SEISMOACOUSTIC WAVES IN THE COASTAL ZONE

2020 ◽  
Author(s):  
А.Н. Самченко ◽  
А.А. Пивоваров ◽  
А.Н. Швырев ◽  
И.О. Ярощук
Keyword(s):  
Surface Waves ◽  
Coastal Zone ◽  
Sea Of Japan ◽  
Peter The Great Bay ◽  
Experimental Studies ◽  
Low Frequency ◽  
Acoustic Signals ◽  
The Sea Of Japan ◽  
Preliminary Results ◽  
Peter The Great

В статье приводятся результаты экспериментальных исследований распространения низкочастотных акустических сигналов (33 Гц) на побережье залива Петра Великого Японского моря. Источник акустических сигналов опускался с борта маломерного судна в воду, а приемные системы были у береговой черты в воде и на суше. За счет использования трехкомпонентных виброметров стало возможно разделить принятые сигналы на различные типы волн (продольные, поперечные и поверхностные). Получены предварительные результаты расчета скоростных характеристик приходов различного типа волн на виброметры. The article presents the results of experimental studies on the propagation of low-frequency acoustic signals (33 Hz) on the coast of Peter the Great Bay of the Sea of Japan. The source of acoustic signals descended from the board of a small boat into the water, and the receiving systems were at the coastline in water and on land. Through the use of three component vibrometers, it has become possible to divide the received signals into various types of waves (longitudinal, transverse and surface waves). The preliminary results of calculating the speed characteristics of the arrival of various types of waves on vibrometers are obtained.

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