多路相移时间戳IFM算法研究及实现

Research and implementation of multi-channel phase shift timestamping IFM algorithm

提出了一种基于时间戳计数的IFM算法.对基准时钟进行频率倍频和等时延多路移相处理,在测量周期内对被测信号fx以及多路基准时钟并行的连续计数,采用回归分析统计方法对这2组计数值进行计算得到fx频率值.对测量误差进行了分析,实验及对比测试数据表明,该方法在同样的测量条件下能够有效地减小由传统计数测频法中±1量化误差引入的测量误差.能够提高测量分辨率约2～3个数量级,测量误差减少30％以上,测量处理时间优于200 ns.

An improved （instantaneous frequency measurement, IFM） algorithm based on timestamping counting is proposed. The timestaming frequency signal is frequency-multiplied and multi-channel phase shifted;the signal to be tested f~ and the multi-channel timestaming clocks are counted with multi-channel parallel counters continuously in the measurement period. The frequency Offx is calculated using the statistical method of regression analysis from the count values offx and timestaming clocks. The measurement error and uncertainty are analyzed. Compared with tradi- tional method, the experiment results show that this method can effectively reduce the error introduced by the quanti- zation error of ± 1 in traditional method ;the measurement resolution is improved by about 2-3 digits, the measurement error is reduced by more than 30% , and the measurement processing time is less than 200 ns under the same meas- urement conditions.