On the velocity of propagation of a frequency-modulated signal in a strongly dispersive medium
The velocity of propagation of a narrowband, frequency-modulated signal in a medium characterized by a strong dispersion of absorption or amplification may significantly differ from the group…
The Multiport Communication Theory
- Computer ScienceIEEE Circuits and Systems Magazine
The principles of the multiport communication theory are presented and accompanied by a discussion of a number of interesting results of its application to single and multi-antenna radio communications in single- andMulti-user contexts.
On the Use of Start-Stop Approximation for Spaceborne SAR Imaging
- Computer ScienceSIAM J. Imaging Sci.
For the image to stay largely unaffected by Doppler, the frequency shift must be included in the definition of a matched filter, otherwise, there will be a geometric shift (translation) of the entire imaged scene from its true position, and there may also be a slight deterioration of the image sharpness (contrast).
Propagation of signals through a dissipative filter and the negative time delay
The propagation of signals through a one-section RLC-filter suggested in  for obtaining a negative time delay and predicting signals is considered. It is shown that all results and conclusions in…
Distortion of a short quasi-monochromatic signal in a resonantly absorbing medium
Propagation of a short quasi-monochromatic electromagnetic (light or radio) signal (wave packet) is considered. The carrier frequency of the signal is close to the frequency of the absorption…
Focusing of a wave beam in an underwater sound channel
The use of a vertical radiating antenna array for generation of a wave beam propagating in an underwater sound channel along the reference ray trajectory is discussed. The method for selecting the…
RadioAstron: relativistic frequency change and time-scale shift
The plans to launch the RadioAstron space system in the near future and the realization the planned record resolution of 1 microarcsecond will require the precise determination of the satellite…
Signal travel times along chaotic rays in long-range sound propagation in the ocean
Numerical calculations show that, in the presence of weak fluctuations of sound velocity, ray trajectories in underwater acoustic waveguides exhibit a chaotic behavior. According to the findings of…
Ray description of the field of a distributed source in a waveguide
A procedure is proposed for constructing the ray description of the field of a distributed source on a long track. It consists in the generalization of the known transformation relating the mode and…
Reflection of radiation from moving inhomogeneities of a medium: Inhomogeneous wave regimes and the ambiguity problem of doppler frequency shifts
For the problem of the reflection and transmission of monochromatic radiation incident on a moving inhomogeneity of medium characteristics, the regimes for transforming a real frequency into a…