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(11) | EP 1 526 758 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | A 5.1 channel signal output mixer circuit for earphone |
(57) A 5.1 channel signal output mixer circuit for earphone using step gain amplification
unit comprising a filtering gain unit, a mixing gain unit and a noise reduction gain
unit, wherein said filtering gain unit obtaining a bandwidth-adjusted subwoofer signal
from two waveform shaping circuits, said mixing gain mixing said subwoofer signal
with an output signal of a front channel to form a first signal, said noise reduction
gain receiving said first signal for noise removal to form a signal and outputting
said signal to a speaker.
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