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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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Photonic Radio Frequency Memory with Controlled Doppler Frequency Shift
2019 International Topical Meeting on Microwave Photonics (MWP), 2019A photonic Radio Frequency (RF) memory with coherent frequency shift and time gated amplifying recirculating delay line is proposed. It can simultaneously control Doppler frequency shift (DFS) and RF storage time. The coherent frequency shift is realized by the beat between the carrier with acoustic-optic modulator (AOM) frequency shift and sideband ...
Zhidan Ding +5 more
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Quantum interference of biphotons with a Doppler frequency shift
Quantum Electronics, 2016We 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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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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Dynamic Doppler Frequency Shift Errors: Measurement, Characterization, and Compensation
IEEE Transactions on Instrumentation and Measurement, 2015Positioning calibration under dynamic conditions is becoming increasingly of interest for high precision fields, such as additive manufacturing and semiconductor lithography. Heterodyne interferometry is often used to calibrate a stage’s position because interferometry has a high dynamic range and direct traceability to the meter. When using heterodyne
Chen Wang 0003, Jonathan D. Ellis
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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), 2003An 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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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 shifts on high-frequency ground backscatter
Journal of Geophysical Research, 1969Frequency changes (Doppler shifts) of high-frequency radio waves propagated by a changing ionosphere can be observed and measured both for ground backscatter and for ‘point-to-point’ circuits. However, the relationships between ionospheric change and frequency shift are different in the two cases.
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Detection of the Doppler frequency shift in acoustic remote sensing systems
IEEE Transactions on Geoscience and Remote Sensing, 1995Presents a new method of using a tracking filter and phase-locked loop (TFPLL) to detect the Doppler frequency shift from atmospheric acoustic echo signals. Under the constraint of limited signal duration, this method has high resolution in frequency (velocity) and space (height). >
Xiaoyun Xiong, Songnian Zhao, Feng Wen
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Frequency estimation of doppler shift for ionospheric studies
1997Thesis (Ph.D.) -- La Trobe University, 1997.; Submitted to the School of Electronic Engineering, Faculty of Science, Technology and Engineering.
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