The Pseudo Code Phase Modulation Doppler From The Signal Processing Circuit Design And Simulation

The pseudo-code detectors having excellent cut-off performance of the distance and strong antijamming capability and so on merits,is the performance superior radio detector.However the pseudo-code phase modulation detector design and the realization have the high application value and the profound research significance.Above all,the article has carried on the theoretical analysis of the pseudo-random code production principle and the method, the frequency spectrum as well as the autocorrelation function; Then has established the functional block diagram of pseudo-code phase modulation Doppler distance determination system, has built its simulation model with the Simulink software package; has realized the pseudo-code phase modulation Doppler detector echo signal correlation treating processes through the simulation experiment.This paper make full use of the coefficient's symmetric character of the Finite Impulse Response digital filter,schemed out a sort of high efficiency low-pass filter by the means of MATLAB language and FPGA(Field Programmable Gate Arrays).In the process of design, the addition, subtraction, and multiplication operations accomplished by using simple VHDL language, the optimized CSD (canonic signed digit) encoding technology reduced the operation time of multiplication,simulated with the FPGA chip, QuartusⅡsoftware. The graphical comparison and theoretical analysis were finished by MATLAB software.Finally the pseudo-random code signal generating device has designed by QuartusⅡsoftware and realized with Xilinx Corporation's CPLD component XC9572;The modulator circuit has completed by AD8346.Between the pseudo-code signal generating device and the modulator circuit increases the level switching circuit, and the chip has completed the design primarily by MAX4287.The pseudo-random code phase modulator hardware circuit were composed of the above-mentioned 3 parts,the designing,layout wiring work completed with the Protel hardware circuit design software, then the electric circuit board was manufactured and debugged.