Patent ID: 7907680

Claim:
A radio data system (RDS) decoder, comprising: a zero-IF FM demodulator receiving a zero-IF signal; a first mixer having an input coupled to an output of the zero-IF FM demodulator and a feedback signal; a low-pass filter (LPF) unit having an input coupled to an output of the first mixer; a shaping filter unit having an input coupled to an output of the LPF; a carrier recovery circuit having an input coupled to an output of the shaping filter; and a digitally controlled oscillator (DCO) having an input coupled to an output of the carrier recovery circuit for outputting the feedback signal to the input of the first mixer; wherein an RDS subcarrier frequency is determined utilizing only an RDS signal of an FM broadcast signal, and the carrier recovery circuit comprises: a phase error detector having an input coupled the output of the shaping filter; and a digital loop filter (DLF) having an input coupled the output of the phase error detector and having an output coupled to the input of the DCO.