| 摘要 |
PURPOSE:To quicken the locking to an optimum phase by controlling the sweep start and stop of a recovered carrier based on various information relating to the error correction obtained by error detection function at an error correction circuit or the like of a demodulation signal. CONSTITUTION:A voltage controlled oscillator 2 applying a recovered carrier to a demodulation circuit 1, a sweep signal generating circuit 3 sweeping an oscillation frequency of the oscillator 2, a processing circuit 4 applying code error correction of a demodulation signal to detect its error, and a sweep tracking control section 5 controlling the operation of the sweep signal generating circuit 3 base on error detection information are provided and a phase error signal from the demodulation circuit 1 and a sweep signal from the sweep signal generating circuit 3 are used as a control voltage of the voltage controlled oscillator 2 via an adder 6. The sweep tracking control section 5 judges the sweep start or stop based on the error detection information to control the circuit 3, and as error detection information, error correction frequency information by the processing circuit 4 or phase uncertainty elimination information is used. Thus, the stable demodulation is applied. |
