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Laser Doppler velocimeter with optical frequency shifting
Optics & Laser Technology, 1973Abstract A bi-directional laser Doppler velocimeter utilizing optical frequency shifting has been developed. Optical frequency shifting is achieved by using a rotating radial grating. A high diffraction efficiency permits the system to be used in the fringe mode.
J. Oldengarm +2 more
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Dynamic non-uniform phase shift measurement via Doppler frequency shift in vortex interferometer
Optics Letters, 2023A vortex beam interferometer based on Doppler frequency shift is proposed to retrieve the dynamic non-uniform phase shift from the petal-like fringes produced by the coaxial superposition of high-order conjugated Laguerre–Gaussian modes. Unlike the uniform phase shift measurement in which the petal-like fringes rotate as a whole, the fringes due to the
Jingtao Dong +5 more
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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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Optics Letters, 2015
A photonic approach for both wideband Doppler frequency shift (DFS) measurement and direction ambiguity resolution is proposed and experimentally demonstrated. In the proposed approach, a light wave from a laser diode is split into two paths. In one path, the DFS information is converted into an optical sideband close to the optical carrier by using ...
Lu, Bing +5 more
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A photonic approach for both wideband Doppler frequency shift (DFS) measurement and direction ambiguity resolution is proposed and experimentally demonstrated. In the proposed approach, a light wave from a laser diode is split into two paths. In one path, the DFS information is converted into an optical sideband close to the optical carrier by using ...
Lu, Bing +5 more
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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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