集成滤波器的一个典型单元电路的改进

非线性失真问题已成为滤波器设计、制造的主要制约因素之一，其原因在于其拓扑结构中的基本元件和单元电路固有的非线性．本文中研究了一种典型单元电路(Schau-mann元件)的非线性特性，导出了其非线性特性的解析式．同时，在此基础上提出了该元件的改进电路，即采用两个元件构成对称平衡电路结构，实现对输出信号进行代数和运算，并通过对其中一个元件的偏压值的选择来降低改进电路的非线性，获得了理想的线性度．这些解析式对于上述单元电路所构造的各种Gm．C滤波器的非线性分析具有重要作用，其推导方法可以应用于其他类似的电路．

Improvement of a Typical Circuit Unit in Integrated Filters

Nonlinear distortion,one of the primary constraints in filter design and manufacture,is due to the nonlinearity between the elementary components and the circuit units in filter topological structures.In this paper,the nonlinearity of a typical circuit unit(Schaumann component) was investigated and the analytical equations of the nonlinearity were deduced.On the basis of which,an improved circuit of the component was presented.In this circuit,a symmetrical balanceable structure containing two components is adopted to perform the algebraic addition of output signals,and the circuit nonlinearity is lessened by the selection of the partial voltage on either of the components,thus obtaining optimal linearity.These proposed analytical equations are of great use to the nonli-nearity analysis of the Gm-C filters constructed,with the circuit units proposed above and their deduced method being applicable to other similar circuits.