| 摘要 |
PROBLEM TO BE SOLVED: To provide a conference talk, with which the sense of incompatibility in hearing does not occur, while reducing the influence of a background noise added to an audio signal by applying gain arithmetic to the audio signal when the audio signal of a conference participant is lower than an arbitrary threshold level by setting the level in a private branch exchange having a multi-person conference talk function. SOLUTION: The audio signal of 8-bit PCM inputted to a conference talk circuit is converted to a 14-bit linear signal and inputted to a noise removing block 4. In the noise removing block 4, that input signal is compared with a 14-bit linear threshold level set by a control means 9 and by performing the gain arithmetic to the input signal lower than the threshold level on the basis of a preset gain value, even in the conference talk of a large number of people, the background noise can be prevented from being superimposed. When a speaker does not speak, the background noise from the side of that speaker can be remained at a suitable level and outputted.
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