| 摘要 |
PURPOSE: A transmitting unit in a mobile terminal is provided to smoothly execute a call with an unspecified person by removing plenty of noise components from a transmitting voice signal more completely. CONSTITUTION: A transmitting unit in a mobile terminal consists of a main microphone(100), an auxiliary microphone(200), a codec part(300), an adaptive noise canceler(400) and a vocoder(500). The main microphone(100) receives a user's voice signal(sk) and a peripheral noise signal(nk) and outputs the first voice/noise mixed signal(dk) to the codec part(300). The auxiliary microphone(200) outputs the second voice/noise mixed signal(xk) to the codec part(300). The codec part(300) receives the first voice/noise mixed signal(dk) and the second voice/noise mixed signal(xk), converts them into digital signals and outputs the digital signals to the adaptive noise canceler(400). The adaptive noise canceler(400) is comprised of an adaptive filter(410) and a subtracter(420). The adaptive noise canceler(400) receives the first and second voice/noise digital mixed signals(dk,xk) using the second voice/noise digital mixed signal(xk), regenerates a main microphone noise signal(yk), removes the main microphone noise signal(yk) from the first voice/noise digital mixed signal(dk), and outputs the noise-cancelled voice signal to the vocoder(500). The vocoder(500) receives the noise-cancelled voice signal outputted from the subtracter(420) and outputs it to the next block after executing a coding operation.
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