An efficient, pitch-aligned high-frequency regeneration technique for RELP vocoders

A technique for reducing the tonal noises due to harmonic misalignment in RELP vocoders is developed. The method, pitch-aligned high-frequency regeneration, is based upon frequency translation by modulation phenomena of the transmitted baseband signal. The method is reported to give the same tonal noise reduction as a full-band pitch prediction system. A reduced complexity version is implemented in a real-time, single TMS320-based vocoder.