| 摘要 |
An apparatus for reducing the background noise on a telecommunication transmission comprises a first microphone for detecting a first signal 410 which includes speech and background noise, a second microphone for detecting a second signal 420 which includes background noise, a means 450 for calculating the time delay between the first and second signals, a means 460 for time compensating the signals such that the second signal is aligned with the first signal, means for subtracting the second signal from the first signal to produce a third signal, and means for transmitting the third signal, preferably after compression and amplification at 470, 480. An alternative method involves at 630 phase shifting by 180{ the phase of a signal from a microphone exposed to background noise, and then emitting the signal through a speaker at 660 to interfere destructively with the local background noise. Application to mobile telephone handsets is described.
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