模拟Sigma-Delta调制器的系统设计和仿真验证

当Sigma-Delta调制器的前向通道积分器个数为L时,称该调制器为Sigma-Delta调制器.本文首先给出了Sigma-Delta调制器的线性模型.根据该线性模型,并考虑输入噪声的影响,将L阶调制器设计分解为线性滤波网络和非线性量化器的设计.这样,既保证了系统的稳定,又使基带内的量化噪声减至最小,获得了最佳的量化噪声整形,将原来在整个频带内均匀分布的白噪声推向了高频端.设计了噪声传递函数NTF,并对其进行了优化.最后,给出了5阶Sigma-Delta调制器的仿真结果.仿真结果表明,调制器的分辨率主要由噪声传递函数NTF的零极点分布特性决定,本文提出的设计方法是可行的.仿真数据对调制器的设计具有重大意义.

Design of an analog Sigma-Delta regulator and its simulation

When the number of the integrator in a Sigma-Delta regulator's forward path is L, the regulator is called L-step Sigma-Delta regulator. Based on the linear model of the regulator given in the paper, the design of the regulator is attributed to the design of a linear filter net and a nonlinear quantifier with the consideration of input noises. In this way, the system stability is ensured, and the quantified noise in the basic frequency band is also decreased to minimum. The optimized quantified noise shape is obtained and the white noise is put into high frequency band. Furthermore, the noise transfer function (NTF) is designed and optimized. Finally,a 5-step Sigma-Delta regulator is simulated. The results show that the revolution of the regulator depends on the zero-pole distribution property of the NTF. The design method proves feasible and the simulation data is of great importance to the regulator design.