分布式测试系统同步时钟校准的频率测量方法  

Frequency Measurement Method of Synchronization Clock Calibration in Distributed Testing System

作　　者：陈威[1] 张丕状[1] 

机构地区：[1]中北大学电子测试技术国家重点实验室,山西太原030051

出　　处：《探测与控制学报》2009年第5期69-72,76,共5页Journal of Detection & Control

基　　金：重点实验室基金项目资助(9140C12040206060C12)

摘　　要：针对传统的授时系统不适合分布式测试中时间同步的问题,提出了一种利用GPS和无线电广播的方式对分布式测试系统进行时间同步及时钟校准的方法。该方法通过主站提取GPS的时间信息和1 PPS脉冲并编码为授时命令,基站接收到授时命令后,立即解码产生时间同步信号,基站利用该信号对内部时钟进行频率校准,使各基站的时钟达到高精度的时间同步;当校准触发信号有效时,进入时钟校准模式,时钟校准电路在16个1 PPS脉冲内对晶体振荡器的频率进行精确测量,再根据时钟校准原理计算出晶振的偏差以及外部触发事件发生时的校准时间。实验结果表明,时钟校准后,各基站之间事件同步触发误差均为微秒量级,系统可靠性高、实时性好,可以广泛使用。Owing to traditional timing system is not fit for the problem of time synchronization in the distributed testing system.Based on GPS and radio broadcasting,a method of time synchronization and clock calibration is presented.Abstracting the GPS time information and 1PPS pulse and encoding them as timing command,the master station transmits the timing command to other base stations by radio.After the base stations receive the timing command,they immediately produce time synchronization pulses.The base stations use this signal to calibrate their internal clocks,so that the base stations can achieve time synchronization of high-precision when the calibration trigger signal is valid,it enters the mode of clock calibration and the clock calibration circuit measures the frequency of crystal oscillator accurately in sixteen 1PPS pulses,as well as based on the principle of calibration to calculate the deviation of crystal oscillator and calibration time of the external incident.Test shows that the incidents＇ errors of synchronous triggering among stations are microseconds after clock calibration.Therefore,it can be widely used for the high reliability and real-time of the system.

关 键 词：时间同步 时钟校准 分布式测试 GPS授时 无线电 

分 类 号：TN964.1[电子电信—信号与信息处理]