| 摘要 |
PURPOSE:To stabilize the color forming in using an SECAM signal, by providing a gate circuit switching the mode with an external control signal in an IC and stopping the operation of a phase comparator of the APC system only at the SECAM signal. CONSTITUTION:A signal which turns off a gate circuit 31 at the input of the SECAM signal and turns on the gate circuit 31 at a PAL signal is inputted from a control signal input terminal 32. The gate circuit 31 is turned off at the SECAM signal, the operation of the phase comparison circuit 24 is stopped and a phase comparison control output between a carrier chrominance signal switched at each H and an output of a voltage controlled oscillator 26 in free-running is not outputted. In this case, an output of a band pass filter outputted to a converter 5 is controlled with the phase information provided for a reproducing horizontal synchronizing signal inputted from a terminal 15 only. At the input of non-SECAM signal, the gate circuit 31 is turned on and the phase comparison circuit 24 is operative. |
