A pitch compensating quantizer

A new adaptive quantizer for speech digitization has been derived. It is similar to known adaptive quantizers in that it adjusts its dynamic range to match that of the speech waveform. In addition, it further adjusts its range to compensate for the increased signal strength that follows a pitch pulse. The new quantizer bases its adaptation on its own output and no side information is required. When combined with a variable length source coding scheme, the new quantizer offers a significant improvement in signal-to-noise ratio and in subjective speech quality. The technique is applicable to a broad range of digitization methods including adaptive delta modulation and various forms of ADPCM.