Results 291 to 300 of about 118,033 (340)

Quantitative measurement of the Doppler shift at an ultrasonic frequency

American Journal of Physics, 1976
Two ultrasonic transducers, the receiver stationary at the end on a linear air track, and the source mounted on a moving glider, are the basis for a Doppler shift experiment. The source frequency and the shifted receiver frequency are fed into a digital phase detector circuit which produces an output difference frequency with a sinusoidal waveform ...
R. A. Leskovec, R. C. Nerbun
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Frequency Detuning Control by Doppler Shift

2011
In this work, a control strategy for ship parametric roll resonance is developed by changing the frequency of the parametric excitation. This is achieved by varying the ship’s forward speed. This changes the perceived frequency of the waves, known as the encounter frequency (and thus the frequency of parametric excitation), via Doppler shift.
Dominik A. Breu, Christian Holden, Thor I. Fossen   +2 more
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Passive localization from Doppler shifted frequency measurements

[Proceedings] ICASSP 91: 1991 International Conference on Acoustics, Speech, and Signal Processing, 1991
An efficient search scheme for an underwater radiating source is developed by introducing intermediate variables which are products of some of the unknowns. The search dimension is only two, in x-y position, instead of five. The resultant intermediate equations become linear and are easier to solve; the major calculation at each grid point requires an ...
Y.T. Chan, J.J. Towers
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A frequency shift maximum frequency follower Doppler demodulator with amplitude correction [PDF]

Clinical Physics and Physiological Measurement, 1981
A commonly used maximum-frequency follower Doppler demodulator uses a variable-frequency voltage controlled filter that requires two good quality multipliers and can be difficult to set up and stabilise. An alternative presented here has the advantage of cheapness, easy setting-up and amplitude independence over about 25 dB giving the potential for ...
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Doppler Shift Frequency to Voltage Conversion Techniques

1975
Three methods of converting the Doppler signal to voltage proportional to mean velocity are compared. The traditional zero crosser is simple and reliable, however, erroneous readings are obtained in the presence of noise and broad band Doppler signals.
F. D. McLeod, R. E. Daigle, C. W. Miller
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Quantum interference of biphotons with a Doppler frequency shift

Quantum Electronics, 2016
We report a theoretical study of transformation of a biphoton state of light under Bragg diffraction on a travelling sound wave in an acousto-optic modulator (AOM). It is shown that the diffraction of AOM biphotons emitted during the collinear parametric scattering of light leads to a shift of the carrier frequency of a biphoton wave packet, which ...
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Blind Source Separation in the Presence of Doppler Frequency Shifts [PDF]

Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005., 2006
We address the problem of blind separation of sources, mixed subject to possible Doppler frequency-shifts, differing between sources and between sensors. This situation is likely to occur, e.g. in scenarios involving mobile sensors and/or sources, but so far the multiple sources case does not seem to have been addressed (at least not in open literature,
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Absence of the transverse Doppler shift at microwave frequencies

IMTC/2002. Proceedings of the 19th IEEE Instrumentation and Measurement Technology Conference (IEEE Cat. No.00CH37276), 2003
An experiment is described showing that a 36 GHz microwave signal received by rotating antennas or mirrors is not exhibiting the frequency shift ("transverse Doppler effect") predicted by the relativistic Doppler formula. The sensitivity of the apparatus used has been tested to be sufficient for detecting frequency shifts as small as 10/sup -3/ Hz ...
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Non-Doppler frequency shift of Newton waves

Optik, 2018
Abstract The Doppler effect has widely applications in optics, physics, acoustics and cosmology. It is verified in vacuum and linear media such as air and water but the validity in complex materials is rarely tested. Now we propose a counter-example. There is an extra term proportional to the square of relative velocity u 2 for the Newton ...
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Doppler-like frequency shifts generated by dynamic scattering

Physics Letters A, 1990
Abstract Correlation functions of random scattering media are introduced, which generate scattered light whose spectrum is shifted with respect to that of the incident light in a manner which mimics the Doppler effect in its essential features. The shifts may be arbitrarily large.
Emil Wolf, Emil Wolf, Daniel F. V. James
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