| 摘要 |
Audio-frequency amplifier provided with a device for compensating the surrounding noise of the type comprising a means 19 of comparing a first signal, arising from a surround microphone 3 and containing a mixture of surrounding noise and signals arising from loudspeakers, with a second signal, tapped from the output SS of the controlled-gain amplifier 1 employed to control a means of regulating the useful signal/surrounding noise ratio through action on the amplification gain of the useful signal, characterised in that this first signal and this second signal drive in opposition the comparator 19 by way of peak detectors DC 1, DC 2. <IMAGE>
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