Patent attributes
A sigma-delta modulator includes a first adder, a filter, a quantizer and a digital-to-analog converter. The first adder receives an input signal and an analog signal and subtracts the analog signal from the input signal to output a processed signal. The filter receives the processed signal to output a filtered signal. The quantizer receives the filtered signal to generate an output signal. The quantizer works based on a first positive reference voltage and a first negative reference voltage. The digital-to-analog converter generates the analog signal according to the output signal and outputs the analog signal to the first adder. The digital-to-analog converter works based on a second positive reference voltage and a second negative reference voltage. A difference between the first positive reference voltage and the first negative reference voltage is smaller than a difference between the second positive reference voltage and the second negative reference voltage.
