SYNCHRONIZATION CIRCUIT FOR FM MULTIPLEX BROADCAST RECEPTION

摘要

PROBLEM TO BE SOLVED: To prevent the out of the synchronism of DARC(data radio channel) even if AF search is executed and DARC data breaks by inputting a search signal for station selection and substantially stopping the operation of a front protection circuit during a search period. SOLUTION: The output pulse generation timing of a BIC detection circuit 101 detecting BIC(block identification code) contained in reception data is compared with that of a 288-ary counter for block synchronism 102. A matching/non- matching detection circuit 104 judges whether the detection timing is correct or not, and outputs a matching pulse P1 or non-matching pulse P2. The front protection circuit 106 holds the established synchronous state until the number of the output times of the non-matching pulse P2 exceeds a prescribed value. A front protection control circuit 108 inhibits the counting operation of the front protection circuit 106 during the search period for station selection. Thus, the data processing of DARC can be executed from received data immediately after searching terminates.