Design And Implementation Of High Precision Clock Synchronization And Trigger Unit For Distributed Test System

On the path of exploring the unknown,testing technology has always been an important means for humans to understand the world.Among them,distributed testing has developed rapidly due to its rapid economic flexibility.Due to the independence of the clocks of different measuring point devices in the distributed test system,high-precision synchronization cannot be achieved.When analyzing the test data of each test point,it is often sensitive to the time relationship of each data.Therefore,the clock synchronization accuracy of distributed test systems is a key factor related to the correct analysis of test data.Based on the requirement of providing high-precision time-related information for distributed test equipment,the high-precision clock synchronization and trigger unit of the distributed test system is designed and implemented.The high-precision clock synchronization and trigger unit can be networked to achieve clock synchronization accuracy in sub-microseconds.It provides accurate trigger auxiliary signals for test instruments and enables network control functions.This paper first analyzes the development status of distributed clock synchronization methods at home and abroad,and analyzes the implementation of accurate clock synchronization protocol and accurate triggering technology in distributed test systems.The major design is implemented by a MCU chip which supports the PTP protocol and get the timestamp in the MAC layer.The software design is discussed in detail.This article has mainly completed the following work:(1)The transplantation of the LwIP protocol stack is realized,and the node has the capability of building a distributed network through Ethernet.The CMSIS-RTOS real-time operating system was successfully ported to provide reasonable scheduling of tasks and real-time response to events.(2)The clock synchronization software design based on PTP protocol is completed,which enables the constructed distributed clock network to achieve high-precision clock synchronization.(3)Using the timer resources of STM32F407 and the real-time response of the CMSISRTOS real-time operating system to the event,the precise triggering auxiliary function is realized.(4)Designed the LAN trigger control management software to realize the query of the clock status and the remote control of the trigger function in the distributed network.(5)The clock synchronization and trigger unit test platform is built,and the accuracy and precise trigger function of clock synchronization in distributed network are tested and verified.In this paper,the high-precision clock synchronization and triggering unit of the distributed test network is designed,and the related software is developed.Finally,experiments are carried out on the test platform.The experimental results show that the clock synchronization accuracy and precise triggering in sub-microseconds are realized.The auxiliary function has reached the design goal of this topic.