基于GPS与北斗双模授时的压控晶振校频系统的研究与设计

Research on Voltage-controlled Crystal Oscillator Calibration based on GPS&BD Double Time Service

介绍了北斗与GPS双模授时技术,在对高稳压控晶振及其频率特性进行测试分析的基础上,设计了一种基于卫星双模授时的压控晶振校频系统;该系统通过利用GPS和北斗接收机得到的秒脉冲信号,经过性能选优得到标准秒脉冲信号,实现对晶体振荡器频率的校准,获得一个短期及长期稳定度都比较优良的时间频率标准;对压控晶振校频系统的基本工作原理及部分模块电路图进行了说明,实验结果表明,在时间不长于1h内,频率准确度一般优于5×10-12,该系统采用实用方便的方法达到了将晶体振荡器校准到较高指标的目的。

The BD＆-GPS double timing technique is introduced. After testing and analyzing the frequency characteristics of a high accu- racy voltage--controlled crystal oscillator, we designed a system for calibrating of voltage-controlled crystal oscillator. The main idea behind is to use the PPS （Pulse Per Second） signal, which comes from satellite receiver, as a reference to calibrate the frequency of the crystal oscil- lators. Thus, a high quality time--frequency standard is obtained by integrating the long--term stability of satellite time and the short--term accuracy of oscillator. The operating principle and circuit modules of our calibration system are described in detail. It is shown in experiments that the frequency accuracy is higher than 5×10^-11 during the period of maximum one hour.