| 摘要 |
PURPOSE:To speed up the processing time of an audio time axis companding. CONSTITUTION:A time axis companding processing circuit 'A' 22 time axis compands residual signals 42 obtained through decoding RPE parameters 39 by a driving pulse information decoder 21. A time axis companding processing circuit 'B' 24 obtains pitch period parameter signals 44, which are time axis adjusted, from LTP parameters 36. A time axis companding processing circuit 'C' 27 interpolates LPC coefficients and outputs LPC coefficient parameters 47. A short period synthetic filter 26 synthesizes linear PCM signals 48 from the LPC coefficient parameters 47, time axis companding residual signals 43 from the circuit 22 and pitch prediction residual signals 45 obtained from the output signals 44 of the circuit 24 through a long period synthetic filter. A post processing circuit 28 logarithmically compresses the linear PCM signals 48 and obtains PCM output signals 49. |
