Patent ID: 8321776

Claim:
A method of correcting and replacing an erroneous digital source signal sample containing K bits which are compressed to N bits, and added with a parity bit considering parity of M of the N bits which are transmitted and sent to a receiver, wherein N is less than or equal to K, and M is less than or equal to N and wherein signal samples received in the receiver are bit-expanded back to K bit samples as applicable, wherein a parity check is used for ascertaining whether the digital source signal sample received by the receiver is an erroneous signal sample, the method comprising the steps of: choosing M most significant bits from expanded samples of K bits in each said erroneous signal sample and producing M inverted test samples each with K bits, wherein each of said M inverted test samples is obtained by inverting a single one of the M bits and keeping all other (K−1) bits unchanged; passing each of said M inverted test samples through a selected filter and obtaining a filtered output in each case, and for each of said M inverted test samples measuring a difference in value between each inverted test sample and its corresponding filtered output; and, selecting that value of the difference which is minimum, and choosing a corresponding inverted test sample of K bits for replacing the erroneous signal.