2 kbps-2.4 kbps low complexity interpolative vocoder

In this paper a 2 kbps-2.4 kbps low complexity interpolative speech coding algorithm is presented. This speech coder takes the good ideal of waveform interpolation, but adopts a different framework to simplify the system complexity. Band pass analysis is made to estimate the random component in the speech excitation and used to estimate contour of the random prototype in the synthesis procedure. Synthesis algorithm both in the time domain and frequency domain are studied. This paper also presents some important techniques such as one-frame look ahead pitch smoothing algorithm and parameter quantization. This speech coding scheme has been real-time implemented on a 200 Hz personal computer.