Method of digitalized measuring frequency in restriction of sampling rate

Abstract

The invention relates to a method of digitalized measuring frequency in the restriction of sampling rate, and the technique is characterized in that AD conversion is carried out on the frequency signals to be measured; M concerted signals to be measured are in a group; data of two groups adjacent to two seconds are in cross-correlation to obtain a cross-correlation function value; the autocorrelation function values of the two groups are calculated; frequency deviation is calculated according to the cross-correlation amount, thus the actual frequency value of the signals to be measured is thesum of the nominal value and the frequency deviation amount. The invention solves the theory and the technical problem of frequency digitalized precision measurement and provides a full set of total solution for design and realization of frequency digitalized measuring instrument which has high precision and low cost and is based on the technique of a virtual instrument.

Description

technical field [0001] The invention relates to a method for digitally measuring frequency under the limitation of sampling rate, which can solve the problem of digital precision frequency measurement which can solve the limitation of sampling rate, and can solve the problem that the existing analog-to-digital conversion equipment is difficult to meet the sampling rate requirement and cannot realize the frequency of medium and high frequency bands. digital measurement. Background technique [0002] At present, in terms of high-precision frequency measurement methods and equipment, the main equipment includes: Phase Comparator from TimeTech (Germany) and Oscillator Stability Analyzer from JPL (USA). The main frequency measurement principle of these two systems is double mixing time difference measurement, and its main structure is as follows: figure 1 shown. The double-mixing time-of-flight measurement method has a balanced structure and can offset public noise, but because...

AI Technical Summary

Problems solved by technology

The undersampling frequency estimation based on the spectral estimation algorithm is still based on the idea of ​​restoring the original sampling signal. At present, this type of method generally has high design complexity, and the potential for improving accuracy is not obvious. Further improving the accuracy requires equipment. It is also relatively high, so it is difficult to meet the increasing demand for time-frequency measurement accuracy

Some of these reasons have directly led to the limitation of the development of the current digital frequency measurement technology, and it has been better developed and utilized only in low frequency bands such as power lines (50Hz).

[0004] In view of the above two reasons, the existing methods must solve the two problems of simplification of the structure of the high-precision frequency measurement system and the realization of digital measurement of frequency signals in the middle and low frequency bands.

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