LOW-DELAY LOW BIT-RATE VOICE CODER

摘要

PURPOSE: To provide a voice coder reduced in coding delay and low in bit rate by correlatively analyzing an original signal into a residual signal in a short adaptation prediction filter and dynamically calculating the filter coefficient from the reconstituted residual signal. CONSTITUTION: The original sound signal S (n) which is sampled and coded at a high bit rate is correlatively analyzed into the residual signal r (n) through the adaptive short prediction(STP) filter 10 and is coded at the lower bit rate in a device 23. The device 23 senses the coded residual signal r (n) and synthesizes a reconstitution residual signal r' (n). An inverse filter 29 senses the signal r' (n), generates the reconstitution sound signal S' (n) and an STP adapter 27 senses the signal S' (n) and guides the set of the coefficients a (i) for adjusting the filter 10.