| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital/analog conversion circuit of one bit system from which noise such as a click sound is not outputted at the time of a muting operation. SOLUTION: The digital/analog conversion circuit is provided with an offset data generation circuit 3 which generates DC offset, an adder 2 which adds the DC offset generated by the offset data generation circuit 3 to output of a digital filter 1, a noise shaper 4 which performs bit compression processing to digital data outputted from the adder 2, a storage device 8 which stores a periodical signal outputted from the noise shaper 4 when only the DC offset is inputted in the noise shaper 4, a subtractor 7 which subtracts the periodical signal stored in the storage device 8 from the output of the noise shaper 4, a pulse conversion part 5 which converts digital data outputted from the subtractor 7 into 1 bit data and a low-pass filter 6 which converts the 1 bit data outputted from the pulse conversion part 5 into an analog signal. COPYRIGHT: (C)2006,JPO&NCIPI
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