Spectral Method of Measuring of Changes in Time Intervals between Periodic Pulse Sequences

Abstract

Methods of measuring delay time between periodic sequences of pulses are mostly based on the considered parameter direct measurement. The main disadvantage of this approach is the difficulty of ensuring the measurements accuracy in the noise conditions. The aim of this work was to develop a method that provides the ability to accurately measure small changes in time intervals, based on the analysis of the dynamic properties of the spectrum of the delayed measurement signals sum.The developed method essence is to replace the insensitive registration of changes in the delay time between periodic pulses sequences, registration of changes in the parameters of the characteristic harmonic components of the spectrum of the resulting sum of these signals. In this case, only those harmonic components were taken into consideration that have a maximum sensitivity to delay time deviations and a minimum sensitivity to uncorrelated signal parameters changes.To achieve the maximum effect, the influence of the pulse shape of periodic sequences on the measurement accuracy was investigated. Moreover, the trapezoidal form of impulses was taken as the basic as the most common, into which all other forms of impulses can be reborn (triangular, rectangular, sinusoidal, etc.).The calculation results showed the effectiveness of the proposed method in order to reduce the measurement error of small changes in time intervals. In this case, the attenuation error coefficient compared with the existing measurement method amounted to Kwe = 4,78. Using the proposed approach opens up the possibility of improving the algorithmic support of measuring instruments in order to automate them and increase the measurements accuracy.

Keywords

• periodic pulse sequence
• measuring signal
• spectrum harmonic components
• delay time