A Radio Data System (RDS) decoder circuit determines a subcarrier frequency utilizing only a 57 kHz RDS signal of an FM broadcast signal. The RDS decoder includes a zero-intermediate frequency (zero-IF) FM demodulator, a first mixer, a low-pass filter (LPF) unit, a shaping filter unit, a carrier recovery circuit, a digitally controlled oscillator (DCO), a symbol timing recovery circuit, an integrate and dump circuit, a slicer 280, and a differential decoder. The carrier recovery circuit includes a phase error detector and a digital loop filter (DLF). The symbol timing recovery circuit includes a zero-crossing detector, a phase detector and loop filter unit, and a counter.