Accession Number : AD0709680

Title :   RANDOM LINEAR TIME-VARIANT CHANNELS: A SURVEY OF CHARACTERIZATION, PHYSICAL EXAMPLES, SIMULATION, AND MEASUREMENT TECHNIQUES.

Descriptive Note : Technical rept.,

Corporate Author : ROME AIR DEVELOPMENT CENTER GRIFFISS AFB N Y

Personal Author(s) : Ritz,John A.

Report Date : JUN 1970

Pagination or Media Count : 252

Abstract : A survey of the engineering literature associated with random time-variant channels is presented. It is demonstrated that linear time-variant channels may be characterized in a symmetrical manner in terms of time and frequency variables by arranging system functions in (time-frequency) dual pairs. The correlation functions and power spectral densities of these various system functions give a statistical characterization of the channel. All real-life channels and signals have a finite number of degrees of freedom due to restrictions on time duration and bandwidth. This fact is used to derive useful channel models with the aid of sampling theorems and power series expansions. A large number of physical channels exhibit time-variant behavior. Examples of the many physical time-variant channels are discussed and theoretical and experimental results of multipath and Doppler spread are given. (Author)

Descriptors :   (*INFORMATION THEORY, MATHEMATICAL ANALYSIS), (*RADIO WAVES, SCATTERING), IONOSPHERIC PROPAGATION, MULTIPATH TRANSMISSION, DOPPLER EFFECT, LINEAR SYSTEMS, POWER SERIES, TRANSFER FUNCTIONS, MOON, SIMULATION, THESES

Subject Categories : Cybernetics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE