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A frequency shift maximum frequency follower Doppler demodulator with amplitude correction
Clinical Physics and Physiological Measurement, 1981A 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 spectral optical coherence tomography with optical frequency shift
SPIE Proceedings, 2007We propose a new method of flow velocity estimation by analysis of time dependent beating signal using Spectral Optical Coherence Tomography. The oscillatory beating signal is caused by the Doppler shift of light reflected back from a mobile object measured in the interferometric set-up.
M. Wojtkowski +5 more
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Doppler Shift Frequency to Voltage Conversion Techniques
1975Three 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. Daigle, C. W. Miller
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Doppler-like frequency shifts generated by dynamic scattering
Physics Letters A, 1990Abstract 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.
Daniel F.V. James, Emil Wolf
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CANCELLATION OF DOPPLER FREQUENCY SHIFT
1963Abstract : A circuit is described which is capable of canceling first-order Doppler frequency shifts. It has potentialities in the fields of communication, data transmission, and navigation systems for vehicles moving at high velocities. The circuit has the following features: (1) Received and transmitted frequencies at each of the stations involved ...
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Adaptive Doppler frequency shift estimation for OFDM systems
2012 International Conference on Wireless Communications and Signal Processing (WCSP), 2012Orthogonal Frequency Division Multiplexing (OFDM) is sensitive to the system frequency offset, while in high speed movement Doppler frequency shift is the main factor which causes the system frequency offset and result in inter-carrier interference (ICI) and degrade system performance.
Qinghua Tian +3 more
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Doppler frequency shift estimation for differentially coherent CPM
IEEE Transactions on Communications, 1990A communication scheme based on continuous-phase modulated (CPM) signals used in conjunction with trellis-coded modulation (TCM) is considered. To keep the complexity manageable, a detection scheme based on differential detection of CPM signals is used.
E. Biglieri, F. Abrishamkar, Y.-C. Jou
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Non-Doppler frequency shift of Newton waves
Optik, 2018Abstract 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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Surface profile detection by transverse Doppler frequency shift
2011 International Conference on Electric Information and Control Engineering, 2011It is a common sense that the Doppler frequency shift is vanished when the speed of a planar interface is transverse to the wave incidence. However, our theoretical and experimental research shows that the Doppler frequency shift is non-zero for a curved interface with even purely transverse speed, and this physic effect can be used to detect the ...
null Lin Li +3 more
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Frequency shift discrimination: Can homing pigeons locate infrasounds by Doppler shifts?
Journal of Comparative Physiology ? A, 1981Homing pigeons can detect small shifts in sound frequency at 1, 2, 5, 10, and 20 Hz. Their thresholds range from a 1% shift at 20 Hz to a 7% shift at 1 Hz. The frequency shifts used were designed to simulate the natural Doppler shifts resulting from changes in flight path.
Douglas B. Quine, Melvin L. Kreithen
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