PACKET INTERPOLATION SYSTEM

摘要

PURPOSE:To compensate the quality deterioration of sound due to the rejection of a packet by utilizing the pitch period of sound included in the decoding signal waveform of an ADPCM code in ADPCM interpolation. CONSTITUTION:A waveform substitution switching part 15 inputs an ADPCM interpolation input signal I(k) and an ADPCM interpolation generation signal IRE(k) and outputs an ADPCM interpolation output signal I0(k). A decoder 11 inputs it and outputs a decoding signal. The decoding signal is accumulated in a buffer memory update part 12, and an autocorrelation value R is calculated in an autocorrelation operation part 16. A pitch extraction decision part 17 outputs a pitch period estimation value PIT by the extraction and decision of the pitch based on the correlation value R. A memory pointer instruction part 13 outputs a decoding interpolation signal IBUFF(PIT) by the control of the estimation value PIT and a packet loss instruction signal L(k). An encoding part 14 encodes the output, and outputs the interpolation generation signal IRE(k).