Patent ID: 6694477
Filing Date: 2004-02-17
Classification: H03M,H04L

Abstract:
A communication channel comprising:(a) a sampler for sampling an analog data signal to generate a sequence of signal samples; (b) a trellis sequence detector for detecting an estimated data sequence from the signal samples and expected samples of valid output sequences defined by a plurality of paths of a trellis, the estimated data sequence comprising a received Reed-Solomon codeword, the trellis sequence detector comprising: a metrics calculator for computing trellis state metrics relative to the signal samples and the expected samples of valid output sequences; a memory for storing a survivor data sequence for each of the plurality of paths of the trellis, wherein the survivor data sequences comprise the estimated data sequence; a memory controller, responsive to the trellis state metrics, for updating the memory; and an error event detector for detecting an error event of the trellis sequence detector, the error event detector comprising: a remodulator for remodulating the estimated data sequence into a sequence of expected samples; a sample error generator for computing a difference between the signal samples and the expected samples to generate sample errors; and an error event correlator for correlating the sample errors with error event samples corresponding to the error event; and (c) a Reed-Solomon error correction code (ECC) decoder, responsive to the detected error event, for detecting and correcting errors in the received Reed-Solomon codeword, wherein the ECC decoder performs the steps of: i. determining whether the received Reed-Solomon codeword comprises errors; ii. determining whether the received Reed-Solomon codeword is correctable; iii. if the received Reed-Solomon codeword is uncorrectable, modifying the received Reed-Solomon codeword relative to the error event; and iv. repeating steps (i) and (ii) at least once.