Optimized And Design Of Radio-frequence Linear Phase Filter

In the high-speed digital communications, lots of filters are used, if filter's phase response characteristic is not matching, it will reduce the reliability of information transmission and increase code error rate. In order to advance phase response characteristic of passive network, this filter puts forward means of settling issues that is applying circuits optimizing technology instead of network synthesizes theory to solve matching problem .The aim is to solve the design of high-powered special filter and Matching network by using the flexible attribute of optimizing technology. The design is needful for the development of communicational technology and difficult to realize by adopting traditional method.The passive linear phase filter is designed for the tenth research institute of China Electronics Technology Group Corporation, it uses for measure and control system of aeronautics and long-distance guided missile, which optimizes both the amplitude response characteristic and the phase response characteristic of the passive network at the same time based on the method of traditional network's integrated design. The key aim of this paper is how to obtain flat group delay characteristic at pass band and bigger decibel at prevent band.Group delay characteristic is used frequently when designing filters. Because it is phase differential to frequency, if group delay obtain flat curve, that phase curve is approached to a beeline. The paper proposes to a method that how to adjust parameters of components to make the curve of phase-frequency approach a perfect beeline. First, a beeline is made with lease two-multiplied at phase-frequency coordinates. This beeline is believed as phase perfect curve. Put phase curve close in upon this beeline. New component value is gained. The extent of close in upon is respected to precision of optimized program. New phase curve is gained according to new component value. A new beeline is made as new phase perfect curve. Repeat this process till the extent of close in upon accord with requested condition.The result of example shows the method is better than those which are designed by custom network integrated design method.