一种基于信号补偿的频率测量方法

Frequency measurement algorithm based on signal compensation

提出一种通过对被测信号脉宽进行补偿处理以提高频率测量精确度的方法。采用多路单稳态脉冲信号作为补偿信号分别对被测信号脉宽补偿,各组补偿信号脉宽均匀递增且增量总和为一个基准信号周期,选取被测信号补偿后对应的基准信号计数值跳变时刻前后相邻的2组补偿信号脉宽平均值作为理想补偿信号脉宽,最后根据补偿后被测信号和理想补偿信号脉宽获得被测信号的频率。误差分析和测量不确定度评定表明该方法测量精确度由相邻补偿信号间的脉宽增量决定。实验数据证明该方法在保证测量速度的同时有效减小了频率测量中固有的1个基准信号周期的测量误差。

A high precision frequency measurement algorithm based on signal compensation is proposed. Using the method, the measured signal is compensated with multi-channel monostable signals, whose pulse widths increase at a linear interval and the total increment equals to one-reference-pulse cycle. The average width of two adjacent compensation signals that occur when the count value of the reference-pulse counter jumps is selected as the ideal compensated signal width. Finally, according to the corresponding widths of the compensated measured signal and ideal compensated signal, the frequency of the measured signal is obtained. Error analysis and measurement uncertainty evaluation show that the test accuracy of the method is determined by the increment of the pulse width of the two adjacent compensation signals. Experiment data verify that the method could ensure testing speed while effectively reduce the inherent one-reference-pulse cycle test error in frequency testing.