9. The method of claim 7 wherein said step of generating said second error-correcting word comprises generating a second parity word in response to the interleaved N information words and first error-correcting word.
7. The method of claim 4 wherein said step of encoding the respective odd and even information words in an error-correcting code further comprises generating a second error-correcting word in response to the interleaved N information words and first-mentioned error-correcting word; further interleaving the N information words and the first and second error-correcting words; and inserting the further interleaved words into said transmission block.