模拟滤波器群时延的优化设计

为解决滤波器幅频特性算术对称性和相位平直度之间的矛盾,提出了一种基于极点放置技术和电路改进技术的滤波器优化设计方法,即在网络综合法设计的滤波器电路基础上,利用极点放置技术和电路改进技术对电路结构进行改进,然后用最小二乘法使群时延特性逼近一条直线,同时利用无约束优化算法对整个电路进行优化使幅频特性线性对称。仿真结果表明,该方法能够使滤波器幅频特性算术对称,通带内能得到较好的群时延特性,而且电路结构简单,阶数少,插入损耗低。

Optimization Design of Analog Filter's Group-delay

As for the contradiction between the filter’s amplitude-frequency characteristic arithmetic symmetry and the phase-frequency straightness,the paper is focus on an optimization design method based on pole placement technique and circuit improvement technique.Improving the circuit designed by network synthesis method,then optimizing the group-delay to a straight line using least square method,and simultaneously the circuit is optimized by unconstrained optimization method to obtain arithmetic symmetrical amplitude-frequency characteristic.The simulation results indicate that the proposed method can get arithmetic symmetrical amplitude-frequency and preferable group delay characteristics in pass-band.The designed circuit has merits of simple structure,less order,and lower insertion loss.