| 摘要 |
PURPOSE:To obtain a stable burst lock by outputting a waveform locked by one wave of a burst signal as a referenc signal on the basis of a horizontal synchronizing signal. CONSTITUTION:This circuit constists of the burst signal circuit B consisting of a burst signal separating circuit 22, a phase matching circuit 23 for the burst signal, a saw-tooth wave generator 24, and the servo circuit S consisting of a sample holding circuit 26, A/D converter 27, D/A converter 28, edge pulse generator 29, and monostable multivibrator 30, the waveform forming circuit for the reference signal consisting of a delay type FF31 and monostable multivibrators 32 and 33, a synchronizing signal separating circuit 25, three microprocessors CPUs for deciding operation, an AFC circuit 40, and a separating circuit 41 for a vertical signal. On the basis of the horizontal synchronizig signal, one wave of the burst signal is phase-compared and the monostable multivibrator 30 is controlled by the phase comparison output to make a burst lock. |
