Serial data from a C-MAC, D-MAC or D2-MAC television signal is applied over line (1) to a serial data to error conversion unit (2) which produces a 3-bit error signal when the applied data is compared with a W1 sync. word. The error signal is applied to comparators (6 and 7) whose other inputs receive...http://www.google.com.au/patents/US4713692?utm_source=gb-gplus-sharePatent US4713692 - Method and apparatus for deriving frame interval signals
