| 摘要 |
PROBLEM TO BE SOLVED: To reduce distortion caused by a coil of a low-pass filter tbeing a final output stage for a speaker with respect to a digital amplification apparatus used for an acoustic apparatus. SOLUTION: A low-pass filter 28 is added to a feedback circuit which feeds back from a load output terminal 32, and a cut-off frequency of the low-pass filter 28 is defined as a frequency in the vicinity of edge resonance or division resonance of a speaker 33 connected. The low-pass filter 28 separates distortion in a band where the effect of the speaker 33 is considerable, and a band in which the effect of a digital amplification apparatus 20 is considerable, and thereby attaining suppression of distortion in the latter band, so that the feedback circuit is simplified. COPYRIGHT: (C)2009,JPO&INPIT
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