Speech Signal Quantization Using Human Auditory Models in Predictive Coding Systems

A speech compression system called "Transform Predictive Coding", or TP C, provides for encoding 7 kHz wideband speech (16 kHz sampling) at a target bi t- rate range of 16 to 32 kb/s (1 to 2 bits/sample). The system uses short-term and long- term prediction to remove the redundancy in speech. A prediction residual is transformed and coded in the frequency domain to take advantage of knowledge in human audito ry perception. The TPC coder uses only open-loop quantization and therefore has a fairly low complexity. The speech quality of TPC is essentially transparent at 32 kb/s, very good at 24 kb/s, and acceptable at 16 kb/s.