Bell Telephone Laboratories

John Francis Moran

Earl F Brown

A pulse code modulator utilizes a predetermined bit, which is the least significant bit in each code group, to indicate the polarity of the signal amplitude sample whose magnitude is represented by the immediately succeeding code group. Since variations in magnitude change the value of the predetermined bit in a more or less random fashion and the same is true of the polarity of the samples to be encoded, in the course of the encoding process there is a relatively high probability of occasions when the magnitude and polarity will call for the same value of bit. When there is a disagreement in bit value for the magnitude and polarity, the predetermined bit in each code group is forced to indicate the correct polarity. Additional bits in each of these code groups may also be changed to provide the most accurate magnitude information with the corrected polarity information.

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Holmdel, NJ, United States of America

John Francis Moran