| 摘要 |
PROBLEM TO BE SOLVED: To improve the S/N ratio of an A/D converter composed of a band-passΔΣmodulator. SOLUTION: The A/D converter which converts an analog input signal Vin into a digital output signal Vout is composed of the band-passΔΣmodulator. The band-passΔΣmodulator includes resonators 92 and 94 which have band-pass characteristics at a predetermined frequency f0 and attenuation characteristics at other frequencies, a quantizer 95, and a local D/A converter 96. A signal of the difference between the analog input signal and a local analog signal of the local D/A converter 96 is supplied to the resonators 92 and 94. The A/D converter further includes an adder Add for supplying the analog input signal to an input of the quantizer 95. Signal transfer circuits 103, 104, and 101 which reduce influence on input of the resonator 92 due to a spike noise of the quantizer 95 are connected between an input of the adder Add and the input of the resonator 92. COPYRIGHT: (C)2008,JPO&INPIT
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