Design Of High Resolution Sigma-delta Modulator

Sigma-delta modulators, combined with oversampling, effectively attenuate the in-band quantization noise in the output signal and enhance the signal-to-noise (SNR) through the shaping of the quantization error, thus they make it is possible to do high-resolution converter using coarse converters. Compared with their Nyquist Rate counterparts, oversampling sigma delta A/D and D/A converters, taking the advantage of state of the art VLSI technology featured increasing scale and speed, transfer the pressure of high resolution to digital system and greatly release the requirement on the performance of analog circuit. Sigma-delta is the one of most significant technology in the converter domain. In china, the research fall a large distance behind the international. There are few converters having the resolution above 16 bit are produced.This paper made a research on 16 bit resolution sigma-delta converter design . The multi-stage structure was used which greatly reduced the complexity of stability. And made an emphases discuss on the Noise, offset, mismatch which was a difficulty in every design. The first part of the thesis introduces the development of sigma-delta data conversion concisely. A detailed description of the principle and implementation of sigma-delta A/D conversion is presented in the second part. In the third part and the fourth part, the structure and circuit design was introduced, and the simulation result was presented in the fifth part, then gives the conclusion.