No abstract

No abstract

No abstract

No abstract

In a DPCM video digital data communication system each scan line of a video frame is refreshed with PCM data over a refresh cycle comprising a plurality of frames. Refresh generators at the transmitter and at the receiver are synchronized with an initialization signal and then run asynchronously to select scan lines for refresh. The refresh generators each employ counters for counting a selected number M, which has no factors in common with the number of scan lines of a frame, to