A NEW DIGITAL IMPLEMENTATION OF THE RDS IN THE FM STEREO

In this paper we deal with some of the main blocks which consist a ste reophonic RDS modulation system. As such we consider the 19 KHz pilot tone of the FM stereo, the 38 KHz subcarrier modulated by the differen ce of the two stereo channels and the 57 KKz subcarrier of the RDS dig ital signal. Also, a digital substitute of the biphase signal generato r required for coding and shaping of the RDS data preceding the balanc ed modulator, is considered. The substitution of the balanced modulato r by a multiplying DAC is another consideration. The synthesis of the three carriers takes place by a multiplexed (triple) Direct Digital Sy nthesizer (DDS). The multiplexed synthesizer can be considered indepen dently for the generation of multiple frequencies.