| 摘要 |
PURPOSE:To prevent the omission of an essential pulse and improve sound quality by computing the maximum value and minimum value of the separation between adjacent pulses by analysis frames, and changing a separation expressing range. CONSTITUTION:A pulse separation maximum value detector 9 retrieves the maximum separation of multiple pulses and a pulse separation minimum value detector 10 retrieves the minimum separation of the multiple pulses so as to output the pulse separation maximum value 11 and the pulse separation minimum value 12 to a pulse separation difference computing element 13. The computing element 13 outputs separation difference 17, which is the difference between the maximum value and minimum value of the multiple pulses, so as to be supplied to a quantize bit distribution label output element 14 to determine/output a quantize bit distribution label 18 distributed to an assigned bit in the quantization of the amplitude and separation of the multiple pulses. A multiple pulse quantizer 15 outputs quantized pulse amplitude-separation 20. Three kinds of quantization input, that is, the label 18, a quantized LPC coefficient 19 and the amplitude-separation 20 are appropriately combined into a multiplexed signal to be sent out to the decoding side. On the decoding side, the multiplexing separation of the multiplexed signal is performed and decoded by a decoder 24. A digital input voice signal is reproduced and D/A converted so as to be outputted as analog synthesized voice 30. |
