【作者】 孙振国；

【导师】 何乐年；

【作者基本信息】 浙江大学 ， 电路与系统， 2005， 硕士

【摘要】 sigma-delta调制器与过采样相结合,对量化误差噪声进行整形,有效衰减输出信号的带内量化噪声,提高了输出带内信噪比(signal-to-noise,SNR),使得利用粗转换器进行高精度的模/数数/模转换成为可能。和传统的Nyquist转换器相比,过采样∑-△ADC将提高精度的压力尽量转移到数字环节,充分利用了数字电路规模越做越大,速度越来越高而成本日益下降的发展趋势,在模拟电路部分降低了对性能指标和元器件匹配精度的要求,简化了设计,降低了生产成本。∑-△调制器结构是迄今为止在数字VLSI技术中执行高精度A/D变换最吸引人的方法。而国内的设计水平和国际上有很大的差距,至今很少有高于16位精度转换器量产。 本文研究了16位精度、20KHz频率的数模转换器的设计。本设计采用多级级联(multi-stage)结构,大大简化了系统结构稳定性的设计,并且对电路中难处理的噪声(noise)、失调(mismatch)以及所需运放的带宽和增益做了重点设计和讨论,并且得到运放的增益和带宽分别大于70dB和50MHz可以满足要求,通过对输出信号进行快速傅立叶变换分析,得到输出信号在20kHz频率范围内的信噪比为98dB,达到了16比特的精度。本文第一章介绍了∑-△调制技术的特点、优点和发展情况,并且阐述了设计目标。第二章介绍了∑一△转换器的原理。第三、四章分别介绍了结构设计和具体电路设计,第五章给出了仿真结果和结论。更多还原

【Abstract】 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.更多还原