Process and circuit layout for the recognition of an identification sign (signum) contained in a video signal

摘要

Circuitry for recognizing an authorization code included in a video signal for enabling a subscriber's television receiver, includes quantizing apparatus for coarsely quantizing the received signal. A correlator designed to recognize the authorization code is coupled the quantizer and produces an array of correlation values. The correlation values are coupled to a threshold circuit which converts the correlation values to bistate values. Further circuitry evaluates the distribution of bistate values to determine reception of the authorization code.