Design And Implementation Of Dual Phase Detection Frequency Phase Comparison System Based On FPGA

With the rapid development of modern science and technology, the frequency of detection is high occasion has most important in some accuracy requirement, such as the timing system and high precision electronic instruments. Time and frequency measurement and scientific development is complementary to each other, the accuracy measurement on time reflects the levels of scientific, and technology also promotes timing measuring. In the modern society, the requirement of information transmission and efficient processing has more and more demanding, and the development of high precision time measurement technology is getting more and more attention. Now, the length, voltage and other physical quantities can also be converted to the use of time measurement technology to determine.This paper based on the existence of a regular pattern of the phase difference between the periodic signals, and a new detection technique based on phase coincidence is proposed. For the two frequency signals which the phase difference is closely, by introducing the intermediate frequency, and filling and counting the frequency of the intermediate frequency. Then two sets of curves are combined. This method can eliminat the edead zone and the nonlinear phenomena. and has the advantages, such as high accuracy, easy to implement, small size and high reliability.The innovation of this design is that, the impluse of the two signal is relatively wide, This way will help to fill the impluse and count the numbers, and the high linear phase discrimination curve between 0 and 360 degree is obtained by processing program. In addition, this method which used the intermediate frequency to measure phase difference between the two signals can successfully eliminate the electronic counting error on ±1 “words”, because the intermediate frequency synchronized the impluse and two signsls.Applition the FPGA in the implementation of system function. FPGA, the field programmable gate array, which is instead of discrete components, and reduce the volume of the system. FPGA is a s product which developmented based on programmable devices, suach as PAL, GAL, EPLD. FPGA not only solves the problem of custom circuits, but also overcomes the original programmable gate number limitedshortcoming, this module is very convenient and written by Verilog HDL language, through a simple layout can quickly burn the FPGA chip to test. In the system of the back-end of the simulation, using the graphical programming software Lab VIEW. By processing the the numerical data received from FPGA module and obtain two phase curve. Lab VIEW is a program development environment,which developed by the national instrument NI, and use graphical editing G language programming. Lab VIEW development environment integrates engineers and scientists to quickly build all the tools needed for various applications, designed to help engineers and scientists to solve problems, improve productivity and innovation.The measurement method based on phase point coincidence is a high precision measurement method. In some cases, the resolution can reach 10 ps. By testing the PCB of system, obtain the accuracy of the phase detector is 2.6×10-10, and the average deviation is 0.003 MHz.