一种基于过零点的时延测量方法

信号传输时间（时延）的测量，是雷达、声纳系统的关键技术之一。本文研究了一种基于过零点的时延测量方法，在建立过零点搜索模型的基础上推导得出时延测量的测量结果表达式；定量分析了高斯白噪声条件下过零点时延测量的测量精度，得到测量误差的理论表达式。仿真与实验表明，过零点时延测量精度与信号频率、过零点数目、信噪比密切相关，当信噪比较高时，其测量精度与经典FFT法相当，而优势在于过零点时延测量的算法简单、计算量小，适用于对实时性要求较高的测量场合。

A Zero Crossing Algorithm for Time Delay Estimation

Time delay estimation (TDE) is one of the critical technology in radar and sonar system. This paper proposed a new algorithm for TDE based on zero crossing (ZC). The basic model of zero crossing TDE is discussed, and the mean squared error with additive white Gaussian noise is derived by a theoretic equation. It is shown that the accuracy of TDE is a function of signal-to-noise ratio (SNR), signal frequency and numbers of ZC points. The ZC algorithm approaches a comparable accuracy with FFT method for high SNR, though with low computational complexity and low processing latency. The proposed zero crossing estimator is suitable for real-time applications.