Analog Circuit Characteristic Measurement System Based On FPGA And MATLAB

Electronic measurement often encounters problems with the measurement of transmission characteristics of unknown systems or circuit networks,especially the measurement of system frequency response.At present,traditional frequency response measuring instruments are expensive,complicated in structure,inconvenient to carry,and difficult to maintain,so they cannot be widely accepted by engineers.This thesis combines MATLAB and FPGA technology to propose a new measurement system for analyzing the frequency characteristics of the system.The new frequency response measurement system designed in this thesis is designed and implemented from two aspects of hardware and software.The hardware system mainly includes a high-speed USB3.0 communication part,a high-speed DA transmission part,a high-speed signal acquisition part,and an FPGA control part;the software system mainly includes a point frequency signal source part,a frequency response analysis part,and a serial port communication part.Main tasks as follows:(1)Completed the firmware development of the USB3.0 control chip EZ-USB FX3,and re-enumerated the device from the Cypress special type device into a universal serial device,realized the bidirectional data transmission between MATLAB and EZ-USB FX3 controller;(2)Designed the GPIF II communication protocol between EZ-USB FX3 and FPGA,realized high-speed data exchange between EZ-USB FX3 and FPGA.Completed the communication protocol design of high-speed data acquisition based on AD9226.Completed the communication protocol design based on AD9708 high-speed data transmission.Completed the data cache design of MATLAB and FPGA communication;(3)Improved implementation of the point frequency method in the frequency characteristic measurement method.The design of the point frequency signal source is completed by MATLAB with powerful data analysis and processing capability,which realized the requirement that the excitation signal frequency automatically changes in steps within the specified starting frequency and termination frequency range;(4)Completed the analysis of amplitude-frequency characteristics and phase-frequency characteristics of the system under test based on MATLAB.It saves the hardware cost to a large extent.Completed the drawing of the system frequency characteristic curve and designed a GUI interface for human-computer interaction;The experimental results show that the system can accurately measure the amplitude-frequency response and phase-frequency response of the circuit under test,and has the characteristics of low price,small size and easy to carry.The measurement system has basically reached full digitization,which is beneficial to reduce the size of the instrument,reduce the weight,reduce the cost,and provide convenience for the user to carry.The performance of the system can meet the measurement of the circuit network characteristics required by most analog circuit systems and has high practical value.