The J-Code: A Minimum-Peak Distortion Code.
NAVAL RESEARCH LAB WASHINGTON D C
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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
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