High Accuracy Time Interval And Frequency Difference Measurement Technique Research

This thesis makes a study of high accuracy time interval and frequency difference measurement techniques. The principles of common time interval and frequency difference measurement techniques are introduced, and performance of these techniques is analyzed. Then, a study of sampling phase estimation time interval measurement is made.Firstly, the principle of this method is briefly introduced,and simulations of the relationships between trigger point time stamp estimation error and signal noise ratio, sampling points,andδare made. Simulation results are analyzed.Then, combined the conclusions of simulation analyzations with the fact that the frequency of reference sine signal is constant, a reform is made to sampling phase estimation time interval measurement technique, and a new time interval measurement method is obtained, which calculates value ofδthrough frequency measurement. Simulations and analyzations are made to the improved time interval measurement technique. Simulation results show that the accuracy of time interval measurement improves. The estimation error increases rapidly, as the value ofδincreases from 0 to 0.5 or decreases from 0 to -0.5.At the same time, with the existation of reference sine signal's frequency jitter and system noise, it is difficulty to guarantee the frequency of reference sine signal entirely coincide with discrete frequency of FFT(Fast Fourier Transform).In order to get a small estimation error of trigger point time stamp, a further improvement is made, and windowing phase estimation time interval measurement method is obtained.Simulations and analyzations are made to windowing phase estimation time interval measurement technique.The simulation results show that a small estimation error is achieved, when the value ofδis between -0.2 and 0.2.