Research On Polyphase Filter Banks For The Signal Processing Technology Of Electronic Reconnaissance

In modern warfare, the electromagnetic environment is increasingly complicated.And it demands that the electronic reconnaissance receiver should be a programmable,wide banded system which has entire probability interception capability. Traditionalanalog receiver not only has low frequency estimation precision, but also bad resolutionand processing capability at the multi-signals conditions. As a new type of receiver, thedigital channelized receiver is considered as a good model of EW receiver, and becomemore and more important. This kind of receiver is sensitive, stable and precise in broadfrequency band. With the development of digital signal processing theory, method andlarge scale integrated circuit technique, wideband digital receiver has become aninevitable trend of the development of electronic reconnaissance system.As an important digital signal processing theory, the polyphase filter banks are thetheoretical foundations of the digital channelized receiver. The Polyphaseimplementation is a multi-rate filter structure combined with a DFT designed to extractsubbands from a high-speed input signal. It is an optimization of the standardapproaches and offers increased efficiency in both size and speed.The paper mainly includes the follow three aspects:1. This basic theory of polyphase filter banks is introduced, and the polyphasefilter banks are deduced and simulated with Matlab.As a comparison,thesliding DFT filter is simulated and analyzed..2. Based on the multi-rate signal processing theory, the digital channelizedarchitecture with polyphase filter banks is analyzed and designed in accordancewith the different precision requirements of time-frequency measurement.False response caused by the overlapped area of adjacent channels is analyzed.And a correlation method is proposed to eliminate the false response.3. The FIR filter and FFT(2points,4points,8points) are built in VHDL as the twomost important parts of the polyphase filter banks. All of the modules aresimulated with Modelsim.