Results 251 to 260 of about 118,769 (293)

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.
Daniel F.V. James, Emil Wolf
openaire   +1 more source

CANCELLATION OF DOPPLER FREQUENCY SHIFT

1963
Abstract : 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 ...
openaire   +1 more source

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.
Qinghua Tian, Qi Zhang, Xiangjun Xin, Dahsiung Hsu   +3 more
openaire   +1 more source

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.
E. Biglieri, F. Abrishamkar, Y.-C. Jou
openaire   +1 more source

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 ...
openaire   +1 more source

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 ...
null Lin Li, null Xiangdong Chen, null Xin-min Wang, Tian-lin Dong   +3 more
openaire   +1 more source

Frequency shift discrimination: Can homing pigeons locate infrasounds by Doppler shifts?

Journal of Comparative Physiology ? A, 1981
Homing 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
openaire   +1 more source

Doppler frequency shift in a refractive atmosphere

Journal of Aircraft, 1987
A general derivation is given for the Doppler-shifted received frequency due to source and receiver motion of uniform velocity in a steady-state, refractive medium with spatial gradients in velocity and temperature. The results from three cases of this generalized equation are especially important.
openaire   +1 more source

Correlation-induced Doppler-type frequency shifts of spectral lines

Physical Review Letters, 1989
The question is examined whether there may be scattering media which could generate spectral frequency shifts in radiation from sources that are at rest relative to the observer and yet would imitate Doppler shifts. Scattering kernels of media whose physical properties fluctuate randomly in both space and time are presented which achieve this to a good
openaire   +2 more sources

Analysis of Doppler Frequency Shift Using Actually Measured Frequency-Height Diagram

2007 International Conference on Microwave and Millimeter Wave Technology, 2007
The equations for calculating the phase path and the Doppler frequency shift (DFS) on the basis of the actually measured frequency-height diagram were theoretically derived. As the example of observation, the DFS of the standard radio wave of BPM 10 MHz from the Dalian-Xi'an channel at sunrise was calculated and analyzed.
Zhang Yinghui, Wang Yizhuo
openaire   +1 more source