SYNCHRONIZATION CIRCUIT OF FM MULTIPLEX BROADCASTING RECEIVER

摘要

PROBLEM TO BE SOLVED: To prevent a miscount at the time of frame synchronization when a receiving station is changed over. SOLUTION: A VICS(road traffic, information system) data broadcasting station is defined as F1 and D-GPS(differential-global positioning system) as F2. Here, data counters 101 and 102 execute counting respectively in synchronism with the timings of multiplex data in the stations F1 and F2. Block synchronization is detected by the output C1 of the data counter 101 under reception in the station F1 and by the output BP of BIC(block identifying code) detection 105. When the broadcasting station is changed over from F1 into F2, the output C2 of the data counter 102 is selected by a control signal CONT and block synchronization is detected by the output C2 and the output BP. Besides, the output C1 is normally inputted to a block counter 110 so that the frame synchronization of multiplex data in the station F1 is detected without a miscount even under reception in the station F2.