TELEVISION SYNCHRONIZING SIGNAL WAVEFORM PROCESSING UNIT

摘要

PURPOSE:To obtain a sharp picture without vertical vibration by using the 1st delay means to retard a reproducing signal for 1/2 of the horizontal synchronizing period, using the 2nd delay means to retard only a vertical synchronizing signal for a time in the range of nearly 0-1/2 of the horizontal period and synthesizing the waveform of the two delayed signals. CONSTITUTION:A composite video signal is read by a magnetic head 12 and fed to a reproducing and demodulation circuit 13. The circuit 13 applies an inputted reproducing signal S1 directly to the 1st delay means 14, separates a synchronizing signal S2 from the signal and inverts it and gives the result to the 2nd delay means 15. The 1st delay means 14 consists of a 0.5H delay circuit 16 retarding the input signal by 1/2 time of the horizontal synchronizing period and a 2-contact changeover switch 17. The changeover switch 17 throws contacts 17a, 17b in response to a switching pulse SWP being alternately at a high and a low level and the reproducing signal is fed to a waveform synthesis circuit 18 as a reproducing signal S3 subjected to delay control.