| 摘要 |
PROBLEM TO BE SOLVED: To surely detect a pseudo locked state even when receiving a signal resulting from further frequency-modulating a 4-phase modulation signal with a service channel signal. SOLUTION: An APC signal detection circuit 12 receives demodulated main signal data Dp, Dq and phase error data Ep, Eq outputted from an identification device 9 and generates an APC signal Sa to control a VCO 11. A filter 17 extracts a prescribed service channel signal included in the APC signal Sa. A level detection circuit 19 outputs a detected signal DS1 when a level of he service channel signal Ss outputted from an amplifier circuit 18 is a predetermined level or over. A switch control circuit 16 regards it as mis-detection by the service channel signal and controls a switch circuit 15 not to select a pulse signal Sp for escaping a pseudo locking when receiving a detected signal Dg from a pseudo lock detection circuit 13 while the control circuit 16 receives the detected signal DS1. |
