群时延内均衡的模拟滤波器优化设计

Optimization Design of Analog Filter′s Group-delay Inner Equalization

为解决滤波器幅频特性算术对称性和通带内群时延波动之间的矛盾,提出了一种滤波器群时延内均衡优化设计方法,即在网络综合法设计的滤波器电路基础上,将电路与时延均衡器直接耦合,用最小二乘法使群时延特性逼近一个常数,然后利用无约束优化算法对整个电路进行优化来降低通带内群时延波动。仿真结果表明,该方法不但能使滤波器幅频特性算术对称且通带内的群时延特性波动较小,且阶数少、设计方法简单。

This paper proposes an analog filter＇s group-delay inner equalization optimal design method in order to solve the contradiction between the filter＇s amplitude-frequency characteristie arithmetic symmetry and the groupdelay ripple in pass-band. The group-delay equalizer is coupled to the circuit designed by network synthesis method, then the group-delay is approached to a straight line using least square method, and the coupled circuit is optimized to reduee the group-delay ripple by unconstrained optimization method. The simulation results indi- cate that the proposed method can get arithmetic symmetrical amplitude-frequency and the smaller group-delay ripple in pass-band. The designed circuit has merits of less order and easy to design.