RDS Decoder

摘要

An RDS decoder includes a synchronous demodulator 1 and a data decoder 2. The synchronous demodulator 1 receives a multiplex signal in which an RDS signal based on digital data is superimposed on an FM audio signal and generates a baseband RDS signal from the RDS signal. The data decoder 2 decodes the baseband RDS signal generated by the synchronous demodulator 1 into the digital data. The synchronous demodulator 1 includes a quadrature demodulator 3 which converts the multiplex signal into two baseband signals which differ in phase by 90 degrees, a filter 4 which removes unwanted components having frequencies higher than a predetermined frequency level from the two baseband signals to reduce sample data, and a phase-locked loop 5 which receives the two baseband signals output from the filter and generates the baseband RDS signal to be input to the data decoder from the two baseband signals. The phase-locked loop detects and corrects phase error remaining in the baseband RDS signal.