Patent ID: 9634687
Date: 2017-04-25
CPC Classifications: H03M

Claim:
1. A continuous-time sigma-delta modulator, comprising: a VCO-based quantizer, arranged to generate a thermometer code based on an input signal and a feedback signal; a rotator, coupled to the VCO-based quantizer, arranged to generate a phase-shifted thermometer code based on the thermometer code and a phase shift, and generate a rearranged thermometer code based on the phase-shifted thermometer code to comply with a specific pattern; a truncation circuit, coupled to the rotator, arranged to extract a most significant bit (MSB) part from the rearranged thermometer code, wherein bits with a specific bit interval of the rearranged thermometer code are determined to be the MSB part, remaining bits of the rearranged thermometer code are determined to be a least significant bit (LSB) set, and the truncation circuit comprises: a digital-to-analog converter (DAC), coupled to the truncation circuit, arranged to generate the feedback signal according to at least the MSB part.