Synchronisation circuit for a FM broadcast receiver, for receiving supplementary data transmitted on a subcarrier multiplexed on the FM carrier signal

摘要

Data counters (101) and (102) perform a counting operation which is synchronized with the respective timing of receiving multiplex data from a VICS data broadcasting station and a D-GPS data broadcasting station. While receiving the multiplex data from the VICS data broadcasting station, based on an output C2 of the data counter (101) and a BIC detection output BP, block synchronization is detected. When the broadcasting station is switched from the VICS data broadcasting station to the D-GPS data broadcasting station, an output C2 of the data counter (102) is selected in response to a control signal CONT and block synchronization is detected based on an output C2 and an output BP. Further, an output C1 is always inputted to the block counter (110). Thus, even while receiving the multiplex data from the D-GPS data broadcasting station, frame synchronization of the multiplex data of the VICS data broadcasting station is detected without causing miscounting.