| 摘要 |
PROBLEM TO BE SOLVED: To perform an echo removable with a small memory capacity. SOLUTION: The voice 11 sounded by a speaker is converted into a digital signal 13 through an analog signal processing circuit 1 and supplied to one input terminal of an adder 2. On the other hand, received data 18 are inputted to a voice decoder 8 and an echo canceller delay buffer 7, the received data 18 supplied to the voice decoder 8 is decoded, converted into a voice waveform data 20 by an analog signal processing circuit 9 and then outputted. The received data 18 supplied to the echo canceller delay buffer 7 is successively read with a voice frame as unit by a voice decoder 6 and decoded. It is supplied to the other input terminal of the adder 2, and subtracted from the digital signal 13. The voice data obtained by this operation is decoded by a voice decoder 3 and transmitted. |
