Broadband For Bpsk Modulation And Demodulation Technology Research

As an important part of near range defense system, near range target detection radar demands effective detection and accurate measurement of target in modern battle field environment. Wideband pseudo code technique with the characteristic of accurate range measurement and good anti-jamming capability is ideal for near range target detection.In this paper, the key technique of modulation and demodulation of wideband BPSK signal in wideband pseudo-random code detection system is discussed. The major work of the dissertation contains several points shown below:Characteristic of pseudo-random code is introduced. High speed m-sequence generator is designed by using the software named ISE8.1 and Xilinx's Viterx-II Pro FPGA chip and simulated in the software ModelSim.The modulation principle of wideband BPSK signal is introduced and the spectrum of BPSK modulated signal is deduced. The modulation circuit of BPSK signal is designed based on broadband quadrature modulator ADL5375. The carrier rejection of the modulation circuit is tested.The demodulation principle of wideband BPSK signal is introduced and the anti-noise performance of coherent demodulation system is discussed. The demodulation circuit of BPSK signal is designed based on broadband quadrature demodulator ADL5382. The amplitude and phase unbalance of the demodulation circuit is tested.