DELTA-SIGMA MODULATION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a delta-sigma modulation circuit of a small scale which has a high S/N and can prevent increase of the number of quantizers. SOLUTION: A 1st subtracter 100 calculates the difference between an analog input signalαX and a feedback signal FB which is multiplied byα(>1) by an amplifier 107 and supplied from a feedback delay unit 106. The output of the subtracter 100 is inputted to a 1st integrator 101. Then the output of a 2nd subtracter 103 which calculates the difference between the output of the integrator 101 attenuated down to 1/αby an attenuator 102 and the output of the unit 106 is inputted to a 2nd integrator 104. The output of the integrator 104 is quantized by a quantizer 105, delayed by the unit 106 by a single sample period, converted into the analog signals and fed back to the subtracters 100 and 103. At the same time, the output of the quantizer 105 is extracted as a digital output signal Y.