| 摘要 |
PROBLEM TO BE SOLVED: To provide an audio system and semiconductor device reducing noise caused by variations in manufacturing an operational amplifier. SOLUTION: A digital offset signal (offset value) output from an offset output circuit 30 is input to a digital part of a DAC 10. The digital part of the DAC 10 adds the offset value to an input digital audio signal using a built-in adder and then applies predetermined digital processing thereto. The offset output circuit 30 outputs an offset value measured in advance for canceling a difference of amplitude centers, that is, DC component variations caused by a difference of characteristics among a first operational amplifier A1, a second operational amplifier A2, and a third operational amplifier A3. COPYRIGHT: (C)2009,JPO&INPIT
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