Patent ID: 6345248
Filing Date: 2002-02-05
Classification: G10L

Abstract:
A system for coding speech, the speech being represented as plural speech samples segregated into a frame, the frame being formed of a plurality of subframes, wherein linear predictive coding (LPC) analysis and quantization of the speech samples in the frame are performed to determine an LPC residual signal, the system comprising:lag means for estimating an unquantized pitch lag value within a predetermined minimum-allowed pitch lag and a predetermined maximum-allowed pitch lag for each subframe within the frame; means for obtaining a pitch lag vector comprising the unquantized pitch lag values for each subframe within the frame; a vector quantizer for quantizing the pitch lag vector to generate a quantized pitch lag vector; means for determining a pitch contribution vector for a current subframe, the pitch contribution vector being adapted to the quantized pitch lag vector; codebook means for generating an excitation signal representative of the speech samples of the current subframe; and means for applying the excitation signal of each current subframe to subsequent subframes to provide coded speech for the frame.