SYNCHRONIZATION SYSTEM FOR VIDEO SIGNAL

摘要

PURPOSE:To obtain a deterioration-free output on an video signal receiving screen by deleting or adding data during a vertical synchronizing signal period in accordance with whether input and output data are excessive or deficient owing to a difference in sampling frequency between an A/D and a D/A conversion part. CONSTITUTION:An input composite video signal is sampled with a sampling signal SPA and converted into a digital signal by an A/D converter 3. This converted digital signal is stored in a memory 6 with a strobe signal STA and the storage contents are read out of the memory 4 with a strobe signal STB. The read data is converted into an analog signal by a D/A converter 9 with a sampling signal SPB. When the sampling signal SPA has a higher frequency than the SPB, the number of data stored in the memory 6 increases, so an input N-point control circuit 4 is controlled by a phase detector 8 and a control circuit 10 to inhibit the sampling signal SPA.