Channelized Receiving Techniques Of Wide-band Meter-band Radar

Wide-band digital channelized receiver is an important part of the new generation radar. This system can improve the ability of whole probability capturing as well as resolving the problem of the channels'disequilibrium of analog channelized receiver.In this paper, basic theories of multi-rate signal processing and intermediate frequencyare quadrature sampling are generally reviewed. The ways of intermediate frequency quadrature sampling including LPF, hilbert transform, bessel interpolation and polyphase filter are discussed. The result of the experiment shows the less number of bits of filter are used and the better image frequency rejection ratio is obtained in the principle of quadrature sampling based on the structure of polyphase filter. And it can reduce the operation quantity. The digital receiving techniques of wide-band meter-band radar are researched including the digital mixing frequency and filtering to sampled radio signal, and the processing FPGA of which is discussed easily. To the wide-band meter-band radar working in 100MHz, the channelized receiving scheme based on polyphase filter is researched, which is used to realize the channel separating of multi-channel signals(the signals of different frequency). The model , which uses FFT to realize channelized processing to multi-channel signals, can reduce computational complexity comparing with traditional LPF receiving method. The simulation results show the channelized receiving method based on polyphase filter adapts to the wide-band meter-band radar working simultaneously in multi-carrier frequency(channel), and it can be used in other occasions of multi-channel working simultaneously.