Patent ID: 7583215

Claim:
A semiconductor integrated circuit, comprising an A/D converter constructed with a non-quadrature band pass ΔΣ modulator and converting an analog input signal into a digital output signal, wherein the band pass ΔΣ modulator includes a resonator responding to the analog input signal to show a band-pass characteristic at a predetermined frequency and show an attenuation characteristic at a frequency different from the predetermined frequency, a quantizer to which an output signal of the resonator is supplied, and a local D/A converter to which an output signal of the quantizer is supplied, the band pass ΔΣ modulator produces a signal of difference between the analog input signal and an output of a local analog signal of the local D/A converter, and supplies the resultant signal to the resonator, and the band pass ΔΣ modulator further includes an adder for supplying the analog input signal to an input of the quantizer, wherein the resonator, the quantizer and the local D/A converter operate in response to a sampling signal having a predetermined frequency, and the predetermined frequency of the sampling signal is set so as to have an error from a quadruple of a highest frequency of the analog input signal.