ADPCM decoder including packet loss concealment method in ADPCM codec and PLC circuit

摘要

PROBLEM TO BE SOLVED: To provide a method of concealing packet loss in ADPCM codec, and an ADPCM decoder with a PLC circuit.SOLUTION: The present invention relates to a method of concealing packet loss in ADPCM codec as well as to an ADPCM decoder with a PLC circuit. The method is characterized in that, in a predetermined transition period between a correction signal (x) and substitute signal (x) supplied by the PLC circuit, difference ((d) between the substitute signal (x) and a computed prediction signal (x) in each subband is combined with a dequantized prediction error (d) to receive a dequantized combined prediction error (d) which is added to the prediction signal (x) to obtain a combined transition signal (x) which is used to serve as a reference for an output signal (x=x) during the transition period as well as to adapt all decoder parameters.SELECTED DRAWING: Figure 3