Patent ID: 6681204
Filing Date: 2004-01-20
Classification: G10L

Abstract:
A signal coding apparatus comprising:normalization means for removing correlation of an input signal waveform based on parameters obtained by carrying out linear prediction coding (LPC) analysis and pitch analysis on the input signal on a time base and outputting a LPC prediction residual signal, wherein said normalization means comprises a LPC inverse filter for outputting said LPC prediction residual on the basis of LPC coefficients obtained by said LPC analysis and a pitch inverse filter for removing the correlation of a pitch of said LPC prediction residual on the basis of pitch parameters obtained by said pitch analysis, and said pitch parameters are derived from a pitch lag and corresponding pitch gain vector for three sample points around said pitch lag; orthogonal transform means for carrying out an orthogonal transform operation on said LPC prediction residual signal; quantization means for quantizing an output of the orthogonal transform means; and coding means for encoding said pitch parameters and said quantized output of said quantiztion means.