| 摘要 |
PROBLEM TO BE SOLVED: To suppress deterioration in an analog output signal in varying an amplitude in a digital signal region and reduce the error between an output set value and an actual output signal level, in a digital volume having a function of adjusting the amplitude of an audio signal. SOLUTION: A first DA converter 1 converts a digital input signal after multiplied by a positive pole side coefficient into an analog signal, and a second DA converter 2 converts a digital input signal after multiplied by a negative pole side coefficient into an analog signal. An output means 5 outputs the difference between the analog signal by the DA converter 1 and the analog signal by the DA converter 2 as an analog output signal. A control means 11 decides values of the positive side coefficient and the negative side coefficient corresponding to an output set value of the analog output signal on the basis of a proportion set for each of the predetermined number of regions concerning the output set value of the analog output signal. COPYRIGHT: (C)2007,JPO&INPIT
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