DIGITAL COMMUNICATION SYSTEM AND METHOD

摘要

A speech digitizer is disclosed including an analyzer for generating power and filter coefficient parameters representative of an analog speech waveform. The digitizer also includes a pitch detector for generating a digital pitch parameter substantially representing the fundamental periodicity of the waveform and including range restrictor means for restricting the pitch signal to a range of pitches within a predetermined tolerance if the average pitch of the periodicity signal is below a predetermined level. The pitch detector also includes means for determining the number of extreme maximum and minimum points within a predetermined range of an absolute magnitude difference function thereby generating a structure number signal representing a voiced event. The digitizer includes a voicing detector for generating a three-level voicing/unvoicing parameter representing whether the speech waveform is voiced or unvoiced.