Pitch quantization in low bit-rate speech coding

This paper describes a new pitch quantization method for low bit-rate speech coding systems. The logarithm of the pitch period is quantized in a combination of two uniform quantizers, one working directly on logarithmic pitch values and the other working on the difference between current and previous logarithmic pitch. The best of the two output values is transmitted to the receiver. This scheme can exploit both redundancy in the signal and properties of the ear to achieve an efficient quantization. Listening tests show that the proposed scheme allows the pitch parameter to be quantized using 4 bits, with no degradation in audible quality.