An AM-compatible hybrid modulation for broadcasting

A novel method of digital-analog hybrid modulation compatible with current amplitude modulation broadcasting is proposed. This approach is based on double sideband with reserved carrier (DSB-RC) modulation, which is commercially used by broadcast stations. The major modification of DSB-RC is to replace the sine carrier with a well-designed quasi-carrier-the one that is modulated by M-ary Phase Position Shift Keying (MPPSK). This quasi-carrier, on one hand, guarantees a qualified modulation index as the sine carrier does, on the other hand, can convey digital information. Computer simulation demonstrates that the hybrid modulation has good backward compatibility and excellent bit error rate performance.