| 摘要 |
PROBLEM TO BE SOLVED: To detect and prevent the pseudo lock of a carrier reproduction loop. SOLUTION: When it is detected the carrier reproduction loop is locked in a demodulator 6 and the frames of data from the demodulator 6 cannot be synchronized, the generation of pseudo lock is judged and a detecting signal (c) is outputted. Corresponding to the detecting signal (c), a timer 22 is started and counted up. When the timer 22 becomes a prescribed value, an address counter 23 is counted up and correction data are read out of a correction data memory 24 by an address signal. The correction data are added with tuning data and inputted to a programmable divider 15 and a local oscillation frequency is fine controlled. Until getting out of pseudo lock, the address signal is updated. |
