DISC CONTROLLED INTERLACED SCANNING RASTER

摘要

Apparatus for scanning the frames of a continuously moving information bearing medium in a television field pattern including a plurality of spaced horizontal lines controlled by a horizontal sweep signal having a predetermined horizontal sweep frequency. A predetermined sweep frequency of the horizontal sweep signal is produced by a horizontal oscillator whose frequency is varied by a control signal produced by a phase detector. A feedback circuit interconnects the output of the horizontal oscillator and one input terminal of a phase detector. The other input terminal of the phase detector is adapted to receive a sync signal having a frequency equal to an integral submultiple of the predetermined horizontal sweep frequency. The phase detector responds to the horizontal sweep signal and the detected sync signal to produce the control signal, the magnitude of which is dependent upon the phase difference therebetween.