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.

Abstract: The communication system, which is especially useful for pay TV, comprises a central station and a plurality of remote stations. The central station includes means for transmitting pay TV programs to the remote stations, and each remote station includes a circuit for transmitting information signals to the central station. Each of the remote stations is adapted to transmit its information signals randomly to the central station so that a relatively large number of remote stations can operate, without interference, with a single central station. In one arrangement, the central station directly reads the information in the received signals to determine the status of the remote station. In a second system, the central station receives randomly transmitted signals from each room, and it also receives signals from the program transmitter.