Tracking error recognition in reproduced digital signals

摘要

A conventional multiple recognition unit provides a multiple error signal whenever digitally coded television signals supplied in successive data blocks to the error recognition unit finds by reference to check-words that the error correction capabilities of the unit are exceeded in any data block. In order to determine when such multiple errors are related to faulty tracking, the multiple error signals are prolonged in duration, overlaps between the multiple error signal and a preceding prolonged signal are detected, and the latter are then integrated. The level of the integrated signal determines the likelihood or presence of tracking error.