| 摘要 |
PURPOSE:To remarkably shorten a time until a reproducing signal is outputted from a demodulation circuit after pull-in is started by initial capture by a DLL circuit and to reduce an unnecessary power consumption by providing a lock information generation circuit. CONSTITUTION:The lock information generation circuit 11 is equipped with a lock detection signal generation circuit 20 and a lockout detection signal generation circuit 21, and the pull-in is started based on a phase comparison signal outputted from a phase comparator circuit 8, and after it succeeds in the pull-in, a lock detection signal is generated, and it is supplied to the demodulation circuit 2. Also, it is checked whether or not the DLL circuit is locked out based on the value of a voltage control signal outputted from a loop filter circuit 9, and when the lockout is detected, a lockout detecting signal is generated, and it is supplied to the demodulation circuit 2. In such a way, the lock operation of the demodulation circuit 2 is started when a pull-in operation is started by the initial capture of a digital match filter, etc., b the DLL circuit, and the operation of the demodulation circuit 2 is stopped when the lockout is detected. |
