Abstract: Successive data words are distributed to a plurality of respective channels to form successive data blocks, each data block being comprised of the data words in the plural channels. A first error correcting code is generated as a function of the words included in the data block, this first error correcting code being adapted for use in correcting at least one word which may be erroneous in the data block, as when the data block subsequently is received or reproduced. The data words included in the data block are selectively delayed, by different respective time delays, to form a time-interleaved data block comprised of time-interleaved data words. A second error correcting code is generated as a function of the words included in the time-interleaved data block, this second error correcting code being adapted for use in correcting at least one word which may be erroneous in the time-interleaved data block, as when the time-interleaved data block subsequently is received or reproduced.

Abstract: A technique is disclosed for preventing errors in a PCM error-correction decoder of the type supplied with successive transmission blocks, each comprised of time-interleaved PCM, error-correction and error detection words, wherein the transmission blocks are selectively supplied from first and second data sources such that an error interval is produced as a function of the transition period during which the selection of the data sources is changed over from one to the other. According to this technique, the presence of an error in a supplied transmission block is detected, and each of the time-interleaved words included in that transmission block is identified as being erroneous. The transmission block is time de-interleaved to recover a de-interleaved block comprised of de-interleaved PCM and error-correction words. An erroneous PCM word in the de-interleaved block is corrected as a function of the remaining non-erroneous PCM and error-correction words in that de-interleaved block.