Research On Signal Processing Algorithm For Channelized Receiver With FPGA

The electromagnetic signal environment is complicated and changing fast in modern battlefields, and is charactered with high density, plenty of multi-band and great bandwidth, which demands electronic reconnaissance receivers with better performance. Digital channelized receivers are of great potential, but their performance is restricted by the rate of ADC sampling and the quantization of ADC, and it can’t satisfy the demand of large dynamic range and large instantaneous bandwidth simultaneously at the present stage.The problem of the cross-channel signal is inevitable for channellized receivers, so the judgment and eliminating false signals is of great importance in channelization. It requires high SNR to eliminate false signals with IFM. And it will be of no use to do judgment when many signals arrive at the same time in one channel. This paper mainly discusses the problem of cross-channel signal in coarse division and studies an effective method to eliminate false signals. Judgment will be done after detecting all the signals with channelized instantaneous frequency measurement. This method can also deal with multiple signals. Meanwhile, a method of frequency measurement called ap FFT-Phase Deducted Method, which is based on FFT algorithm, has been proposed. First, signal is processed with all-phase measurement. Then, all signals should be detected by FFT algorithm. It can obtain high frequency measuring accuracy with a few channels and performs well on multiple signals. In addition, the effect of windowed FFT on frequency measurement is talked about. In the situation where there is only one signal or multi signals whose amplitude discrepancy is not great, the rectangular window is applicable. In the case that amplitude discrepancy of multi signals exists, windows with low side lobe level are supposed to be acceptable.At the end of the paper, FPGA software design for the channelized instantaneous frequency measurement and judgment algorithm has been completed. This solution has some value in engineering.