Accession Number : AD0783949

Title :   The J-Code: A Minimum-Peak Distortion Code.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Jewett,W. M.

Report Date : 23 JUL 1974

Pagination or Media Count : 20

Abstract : The transmission of a PCM symbol on a slowly fading Rayleigh channel was examined from the standpoint of minimizing peak distortion from transmission errors. An encoding technique was defined for M-ary DPSK (differential phase-shift keying) wherein multiple values were assigned to the guard band so as to cause peak distortion to be a linear function of the phase error. Comparisons were made of the use of a Gray code and the natural binary code, with a guard band evenly divided into two symbols. The newly devised J code resulted in a lower probability of high peak distortion than either of these two encoding techniques. The mean square distortion of the J code for a slowly, fading Rayleigh channel is shown to be lower than that obtained for the natural binary code with a guard band of pi, and at very low signal-to-noise conditions it is better than the natural binary code with an optimum guard band of 0.4pi. (Author)

Descriptors :   *Coding, *Radio transmission, Pulse code modulation, Distortion, Signal to noise ratio

Subject Categories : Cybernetics
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE