Results 301 to 310 of about 118,033 (340)

Precision of laser frequency measurements based on the Doppler shift

Soviet Journal of Quantum Electronics, 1976
An estimate is obtained of the precision of laser frequency determinations involving radiofrequency measurements of the Doppler shifts. It is shown that the method does not differ basically from that of interference fringe counting and it cannot ensure a high precision.
A K Toropov, D A Solomakha
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Absence of the relativistic transverse doppler shift at microwave frequencies [PDF]

IEEE Transactions on Instrumentation and Measurement, 2003
An experiment is described showing that a 33-GHz microwave signal received by rotating antennas 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 which ...
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Open-loop receiver for MSK with Doppler frequency shift

IEEE GLOBECOM 1998 (Cat. NO. 98CH36250), 2002
An open-loop digital receiver performing simultaneous carrier phase/frequency estimation and block (two-bit) detection is proposed for MSK signaling in Gaussian channels affected by Doppler frequency shift. Phase estimation and symbol detection are provided by a parallel bank of matched estimators (each one comprising a phase rotation block and a ...
Fernando D. Nunes, José M. N. Leitão
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Atomic Frequency Standard Relativistic Doppler Shift Experiment

28th Annual Symposium on Frequency Control, 1974
An experiment has been performed to measure possible space anisotropy as it would effect the frequency of a cesium atomic beam standard clock in a laboratory on earth due to motion relative to external coordinate frames. The cesium frequency was measured as a function of orientation with respect to an atomic hydrogen maser standard.
H.E. Peters, V.S. Reinhardt
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Doppler shifts on high-frequency ground backscatter

Journal of Geophysical Research, 1969
Frequency 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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Equivalence of Doppler and quantum frequency shifting in Bragg cells [PDF]

Proceedings of the IEEE, 1971
The modified Bragg equation is used to calculate the Doppler shift of light diffracted by a Bragg cell. The calculation yields a solution which agrees exactly with the frequency shift obtained quantum mechanically. This result is in contradistinction to the approximate result published recently. (See R. F. Adrion in Proc. IEEE (Lett.), vol.
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Adaptive Doppler frequency shift estimation for OFDM systems

2012 International Conference on Wireless Communications and Signal Processing (WCSP), 2012
Orthogonal 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.
Dahsiung Hsu, Qinghua Tian, Xiangjun Xin, Qi Zhang   +3 more
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Doppler frequency shift estimation for differentially coherent CPM

IEEE Transactions on Communications, 1990
A 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.
Ezio Biglieri, Y.-C. Jou, F. Abrishamkar
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Surface profile detection by transverse Doppler frequency shift

2011 International Conference on Electric Information and Control Engineering, 2011
It 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 ...
Xin-min Wang, Xiangdong Chen, Lin Li, Tian-lin Dong   +3 more
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On-chip Photonic Method for Doppler Frequency Shift Measurement

2019 International Topical Meeting on Microwave Photonics (MWP), 2019
Photonic Doppler frequency shift (DFS) measurement based on an integrated silicon photonic chip, which contains two cascaded dual-drive-Mach-Zehnder modulators (DDMZMs) and a photodetector (PD), is proposed and experimentally demonstrated. The reference signal is applied to the first DDMZM, while the transmission signal and the echo signal are injected
Shilong Pan, Zhengqian He, Zhengze Cui, Zhenzhou Tang, Simin Li   +4 more
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