Abstract: The disclosure is of a system and method of detecting or identifying a received TV program by forming a database of identifying digital bits for a plurality of programs, processing a TV program by modulating the luminance of pairs of lines of the program and reconstituting the program with said modulated line pairs and the other components of a TV program signal. The reconstituted program is transmitted to a location at which it is decoded to recover the digital identifying bits and comparing such bits with bits in the database to identify the transmitted program.

Abstract: A synchronous digital decoding circuit decodes Manchester-encoded data using a clock regenerating circuit which produces a decoding clock that is continuously adjusted in accordance with detected phase deviations in the received data signal. The Manchester-encoded data are transmitted with high-to-low and low-to-high transitions at the centers of the data bit cells. On the receiving end, a digital state machine, which is coupled to a timer/counter unit, detects whether a transition is on-time, early, or late in each bit cell as compared with the established decoding clock. If the transition is early or late, the state machine produces a correction signal which is used to correspondingly shorten or lengthen the clock count by a predetermined incremental amount. The adjustment of the clock counts on an on-going basis reduces or eliminates the phase deviation and prevents the accumulation of phase error over an extended length of time. In the preferred embodiment, an oscillator input of 1.