Delta Sigma调制器非理想因素建模

Modeling of Delta Sigma modulators non-idealities

提出并构建了开关电容积分器Delta Sigma调制器非理想因素行为级模型,该模型基于Matlab中的Simulink工具,包含开关非线性、时钟抖动、量化器非线性和积分器非线性等调制器非理想因素,能为电路模块的设计提供精确的设计指标.重点研究并实现一种运放非线性直流增益模型,仿真结果表明它能更有效反映奇次谐波失真.同时综合考虑调制器其他非理想因素,例如采样噪声、开关非线性电阻以及运放参数(色化噪声,增益带宽,摆率,饱和电压),仿真得到其对调制器性能的影响.

Non-ideal behavior models of switched capacitor Delta Sigma modulators are presented. On the basis of Simulink in Matlab tool, these models, which involve switch non-idealities, clock jitter, quantizer non-idealities, and integrator non-idealities, can provide performance for circuits design very well. The operational amplifier nonlinear direct current （DC） gain was modeled with emphasis and simulation shows it introduces odd distortion. Other modulator non-ideals such as sampling noise, nonlinear switch on resistance and operational amplifier parameters （colored noise, unit gain bandwidth, slew rate, saturation voltage） were also included, and simulation results display the effects of above non-idealities.