S1A0905

Since 1988 most European national broadcaststations transmit RDScodebeside their audio signals. S1A0905 RDS means Radio Data System andwas originally intended to give people in their cars additional informationabout the weather or traffic(jams). But RDS has grown out to oneig channel of information. Radiostations send their name, the time(with DCF-77 accuracy), their type of music (format) and even more.The digital data of RDS are multiplexed into an FM radio wave using asub-carrier of 57kHz. The transmission rate of RDS data is1.1875kbit/sec.

The S1A0905 transmission rate of RDS data is 1.1875kbit/sec, and RDS dataare encoded by differential encoding method. Then the encoded RDS data are modulated by BPSK using a clockof 1.1875kHz. The modulated RDS data is are modulated by carrier suppressed amplitude modulation using a ubcarrier

of 57kHz. And that signal S1A0905 are multiplexed into an FM radio wave.•RDS data are obtained by demodulating the received RDS modulation signal in RDS demodulator. First, the RDSmodulation signal is extracted from an FM radio wave using a band pass filter. The BPSK signal is obtained from
xtracted RDS modulation signal by a 57kHz carrier recovery circuit. Then the bit rate clock of RDS data isextracted from the BPSK signal, and the BPSK signal is demodulated using the extracted clock signal. Then theRDS data are decoded by a differential decoding method using the demodulated BPSK signal.