一种时间传递系统中调制器时延的数字标定算法

针对传统示波器观察法测量BPSK（Binary phase shift keying,二进制相移键控）调制器时延时存在整码元模糊、噪声敏感、载波初相要求苛刻及标定精度低的缺点,利用软件无线电的相关处理技术,提出一种精密的BPSK调制器时延标定算法.通过高速数字示波器对BPSK调制器的输入基带信号和输出载波调制信号进行双通道同步过采样,对输出信号与输入信号采样值进行循环相关,根据相关峰值对应的样本点序号以及连接电缆的校准时延,计算得到BPSK调制器时延.仿真和试验验证表明：提出的算法不受载波初始相位影响,时延标定上限可达1个伪随机码周期,而且低载噪比情况下也能得到准确结果.数字示波器的通道采样率为10 GSa/s时,采用提出的算法进行BPSK调制器时延标定,标定结果的不确定度可以达到0.2 ns.

A Digital Calibration Algorithm for Modulator Delay of Time Transfer Systems

A high accuracy delay calibration algorithm is proposed for BPSK （Binary Phase Shift Keying） modulators using correlation processing technology of software defined radio to solve problems including whole symbol delay ambiguity, noise sensitiveness, strict demand of carrier initial phase and low calibration accuracy in measurement of the delay of BPSK modulators with a conventional oscilloscope. The input and output signals of the BPSK modulator are oversampled synchronously with a high-speed digital oscilloscope. The sampled input and output signals are pro- cessed using circular correlation. The delay of BPSK modulation is calculated based on the index corresponding to the peak of correlation results and cable calibration data. Simulation results and test verification show that the pro- posed algorithm is independent of the initial phase of the carrier, the calibration limit is up to a pseudo random code period and accurate results can be got even at low carrier to-noise ratio. The calibration uncertainty of delay calibra tion of BPSK modulators is less than 0.2 ns using the proposed algorithm as the sampling frequency of the oscillo- scope channel is 10 GSa/s.