END OF PLAY CIRCUIT

摘要

END OF PLAY CIRCUIT Video disc player pickup circuit recovers picture information in the form of carrier waves, the instantaneous frequency of which varies over a given deviation range in accordance with the amplitude of composite color video signals, in the course of pickup tracking of successive convolutions of the disc record's groove. Succeeding the innermost groove convolution containing recorded picture information are a plurality of groove convolutions containing an end-of-recording signal comprising unmodulated carrier waves at a given instantaneous frequency within said deviation range. Signal processing circuitry of the video disc player includes a sync separator for separating a deflection synchronizing component from the composite color video signals recovered during playback of the groove convolutions containing picture information. Video disc player also includes a defect detector monitoring carrier frequency departures from the given deviation range, and a squelch signal generator responsive to the output of the defect detector. An end-of-play signal generator responds to the continuance for a given time interval of a simultaneous absence of outputs from sync separator and squelch signal generator by generating an end-of-play signal, which is utilized to terminate record playback efforts and to restore pickup apparatus to a rest position.