| 摘要 |
<p>PURPOSE:To restore naturally information at a receiver side even when a change in environmental noise is in existence for a soundless block in the voice packet communication system in which the soundless block not including significant voice information is compressed and the resulting packet is sent. CONSTITUTION:When a packet transmitter 10 detects a soundless frame at a voice detection circuit 120, the transmitter 10 dends a soundless detection signal SS to a period decision circuit 140. The period decision circuit 140 receives the detection signal SS to count a prescribed period, then the circuit 140 sends a period signal SP to a noise level encoder 130. The noise level encoder 130 calculates respectively a means power of period environment noise for each period and sends a noise level code CN for each period. The noise level code CN is added to a control frame by a packet composition circuit 150 and sent for each period. Every time the receiver side receives a packet with a noise level code added thereto, a pseudo environment noise is generated based on the noise level code and it is inserted respectively to the soundless block.</p> |
