时间同步系统短波校时失败分析及解决方法

摘要

The model of coherent automatic gain control(AGC) circuit combining digital and analog method is given to solve the failure of time calibration in the synchronization system. The shortwave receiver adopts the scheme of super heterodyne receiver to find out the reasons of failure according to the characteristics of shortwave timing service. The signal format of shortwave timing service is introduced,the effect of analog noncoherent AGC circuit on the receiver is analyzed that the AGC circuit may distort the amplitude and phase of signal while the response time of the input signal appears to be slowed. The coherent AGC circuit model combining digital and analog method is established through analysis and calculation. The test results prove the effectiveness of the designed shortwave timing receiver. The method provides reference for desig-ning shortwave timing receivers.%针对时间同步系统短波校时失败的现象，给出了一种数模结合实现的相关自动增益控制(AGC)电路模型。短波校时接收机采用超外差接收机方案，结合短波授时的特点，找到校时失败的原因。介绍了短波授时的信号格式，分析了模拟非相关自动增益控制电路对接收机的影响---模拟的自动增益控制电路容易使传输信号的幅度和相位发生畸变，并且对输入信号的响应时间慢。最后通过分析计算，建立了数模结合的相关自动增益控制电路模型。实验测试结果表明，采用此设计的短波校时接收机能解决信号格式及信道失真引起的短波校时的不同问题，对短波校时接收机的设计具有指导作用。