Amplitude phase measuring method

Abstract

The invention relates to a method for measuring an amplitude phase, which comprises the steps as follows: two paths of digital periodic signals are received and obtained, and each path of signal performs self-correlation calculation to obtain amplitude values respectively; after being delayed by one quarter cycle, one path of signal and the other path of signal perform mutual correlation calculation, the product of each amplitude value is divided by an obtained result, and then the phase difference between two paths of signals is obtained through the solution of an inverse sine function. The method has the advantages that the negative phase difference can be measured by a method for solving an arcsine instead of an arc cosine through shifting, thereby the requirement for the actual measurement of an electromagnetic wave logging instrument is met, the arithmetic mean value is further taken through a plurality of times of measurement, thus further enhancing measuring accuracy.

Description

technical field [0001] The invention relates to signal testing, in particular to a method for measuring amplitude and phase. Background technique [0002] At present, the phase difference measurement methods of sinusoidal signals mainly include zero-crossing detection method, spectrum analysis DFT method and correlation analysis method, as follows: [0003] (1) Zero-crossing detection method. The zero-crossing detection method calculates the time difference by judging the zero-crossing time of two signals of the same frequency, and then converts it into a corresponding phase difference. figure 1 It is the schematic diagram of the zero-crossing detection method, and the phase difference calculation formula is: [0004] [0005] Among them, Δt is the time difference between the zero-crossing points of the two detected signals, and T is the signal period. The error of the zero-crossing detection method is related to the number of digits of the data acquisition card, the s...

AI Technical Summary

Problems solved by technology

[0018] From the formula (I), it can be seen that the phase difference can be obtained by seeking the inverse cosine function, and the solution result is between (0, π), but the phase difference of the electromagnetic wave induction logging signal is generally between (0, π / 2), So in theory, this algorithm can meet the requirements, but the two channels of the same frequency signal in the induction logging will undergo a series of processing before entering the measurement method, which will produce a certain phase offset, so that the range of the phase difference becomes (-π / 2, π / 2), so the inverse cosine function cannot get the negative phase, which requires an improved correlation algorithm for calculation

In addition, the existing phase measurement uses more than one measurement error is relatively large

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