| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synchronous detection device capable of improving the stability of the synchronous state of a reproduction signal even if noise is mixed, improving the accuracy of information to be recorded, and accelerating locking of the frequency and phase synchronous processing of the reproduced signal. <P>SOLUTION: A carrier wave reproduction circuit 2 reproduces a carrier wave, and a clock recovery circuit 3 recovers a reception clock. A detection circuit 4 detects a reception wave using the reproduced carrier wave and a recovered clock, and feeds difference (error) information of the detected reception wave, the reproduced carrier wave and the recovered clock back to a monitoring/control circuit 1. A cumulative addition circuit 5 serially adds internal state information of each recovery circuit by the number of set times, and outputs values of adding result by that time every time addition of the set number of times is completed. A mean value calculating circuit 6 calculates a mean value in the corresponding adding section on the basis of the value of adding times previously set from a result of cumulative addition, and outputs the calculated value. A synchronous determining circuit 7 compares the mean value data with the internal state information of the recovery circuit in the case that synchronous processing of each reproduced signal previously set and the reception signal is stable, and notifies switching of a loop band in each reproduced signal from the difference thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
