The Software Design Of Control And Display Module Of Phase Noise Test Equipment

Phase noise is a key problem in many areas of engineering and physics,such as oscillators,radar,the emerging field of microwave photonics,and more exotic fields such as radio astronomy,particle accelerators,etc.With the rapid growth of the demand for high-stability signal sources in many fields,the phase noise of high-stability standard frequency sources is getting smaller and smaller,and the difficulty of measurement is further increasing.In recent years,more and more attention has been paid to phase noise measurement techniques.The phase noise tester can measure the phase noise signal deviating from the carrier by 1Hz-2MHz.The measured phase noise information is transmitted to the upper computer through the design of "analog + digital",and the upper computer will calculate and analyze the received data,draw the waveform and display it.This paper analyzes the software requirements from the graphical interface display,channel and loop state control and data transmission processing,and determines the overall design scheme of the software system according to the requirements analysis.This paper mainly studies the following aspects:1.Graphical interface display function.Graphical interface is the main channel of human-computer interaction,its function modules mainly include: menu selection,waveform drawing,zooming-in/zooming-out of coordinate axis,label information management,file management and other functions.2.Channel and loop state control function.The state frame data is received through the serial port,and the correctly parsed data is sent to the hardware again through the serial port to complete the state control of the channel loop.3.Data transmission and processing function.After the state of the channel loop is configured,the data receiving thread implements the data receiving function by loading the dynamic link library in C#.The software system still needs to do data cross-correlation processing and low frequency defect compensation.4.Low frequency defect algorithm.The system uses phase-locked loop(PLL)technology,which leads to the defect of waveform in low frequency band.The compensation model was established by analyzing the characteristics of the phase-locked loop,and the correctness of the model was verified by MATLAB simulation.Finally,the model was applied in the phase noise tester to realize the compensation of low frequency defects.5.Key technology of software system.The instrument software system also uses a variety of key technologies,the use of events and custom technology to make the system design more simple,user-friendly,the use of multithreading technology to develop software system,make the execution efficiency of the program has been greatly improved.