授时系统中信号单程传输时延的估算直接影响到授时的精度, 环路时延测试是估算单程传输时延的方法之一。在光缆授时系统中光纤的色散特性将导致不同波长光信号在同一光链路中的传输时延存在差异, 基于G.652光纤的色散特性, 提出的时延差精确估算方法, 能够得到这种传输时延的差异。仿真显示来回链路工作波长在1.55 μm附近时, 此方法能够很好地补偿时延差, 从而精确估算信号传输时延。

The time synchronization accuracy depends on the accuracy of the transmission delay measurement of the time signal in the time transfer system. The transmission delay is always achieved by measuring the round-trip path delay using the outgoing and incoming path. But it incurs error due to the chromatic dispersion of the fiber in the time transfer system based on optical cable. A method to count the difference in transmission delay between the outgoing and incoming path is proposed based on the dispersion of the G.652 fiber. The error caused by fiber dispersion can be eliminated when the wavelength of optical signal in the round-trip is around 1.55-μm by using this method, which can achieve the accurate transmission delay of the signal.