Frequency measurement algorithm based on signal compensation

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.