Digital RDS demodulation in FM subcarrier systems

We propose a digital receiver for FM subcarrier systems including the radio broadcast data systems (RBDS) and the radio data systems (RDS). The RBDS receiver is demodulating the 57 kHz modulated digital signal to the baseband RBDS digital signal. It contains carrier Costas loop synchronization techniques, a symbol timing recovery and decoding techniques, and an RBDS decoder. The RBDS decoder is used to recover the digital signal to the information data and sent to the output of the RBDS system. The main functions in the RBDS decoder are block error detection/correction, block synchronization, and block type detection.