Pre-calibration of the phase interpolator of a precision time interval meter

Abstract

The problems of precision measurements of time intervals are considered, the results of which are necessary, for example, to assess the metrological characteristics of the structural complexes of space navigation systems. A precision time interval meter has been designed. The relationship between the meter readings and the size of the measured value is established. A technique for preliminary calibration of a phase interpolator with an uneven quantization step from the composition of a precision time interval meter was developed and tested. The optimal value of the reference frequency was selected and the optimal size of the measuring matrix, consisting of logic gates connected in series, was calculated. The degree of influence of the crystal temperature of the FPGA integrated circuit on the operation of the phase interpolator is determined. The requirements for test signals were developed and the possibility of using the reference signals of the secondary standards of time and frequency (for example, the State secondary standard of units of time and frequency VET 1-7) during the preliminary calibration of the phase interpolator was evaluated. Special software has been developed for determining the boundaries of the sub-quanta of the phase interpolator with a resolution of one picosecond, and the probability density functions of the transition process from one subquantum to the next are calculated. The requirements for the spectral composition of the frequency of the reference signal are given and the frequency detuning of the test signal relative to the reference is determined. Verification of the developed methodology for preliminary calibration of the temporal position of the phase transitions of the interpolator was carried out by repeated calibrations and comparison of the results.