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Possibilities of nonsynchronized phase measurements in single-channel measuring systems

Keywords:

A.S. Glinchenko, O.A. Tronin


The single-channel nonsynchronized measurements of phase shift of the signals divided by a spacing interval of set duration, are based on knowledge or measurement of their frequency. On known frequency of a signal or its estimation it is possible to extrapolate a measured phase of one of signals to the start of measurement of a phase of the second signal and to find their difference. Proceeding from a permissible error of an estimation of signals phase shift, demands to accuracy of frequency measurement or to its admissible instability are in-process defined at known rating value. Spectral methods of measurement of parameters of a signal most match to a solved problem. They provide a joint estimation of signal phase and frequency. It is shown that at high signal-to-noise ratios the estimation of signal frequency under the relation of modules signal and adjacent to it frequency samples of discrete Fourier transform is expedient, and at measurements in noise - its estimation on increments of a phase of contiguous sets of samples of a signal. Using these estimations and the found relationships between duration of a spacing interval and measurement, it is possible to provide measurements of phase shift of signals occurring at different times with accuracy necessary for the concrete application. Attained accuracy of measurements is connected with an error of spectral estimation of phase of a signals. For example, at the signal-to-noise ratio 20 dB, number samples of signal N = 2048 and the Hanning window function its design root-mean-square value makes 0,27°.
References:

  1. Glinchenko A.S., Tronin O.A. Sposob geoe'lektrorazvedki i ustrojstvo dlya ego osushhestvleniya / zayavitel' i patentoobladatel' Sibirskij fed. univ-t. № 2011144054; zayavl. 31.10.2011; polozhitel'noe reshenie o vy'dache patenta ot 30.10.2012 g.
  2. Glinchenko A.S., Tronin O.A. Issledovanie spektral'no-vesovogo izmereniya chastoty' signalov // Cifrovaya obrabotka signalov. 2010. № 2. S. 22–28.
  3. Glinchenko A.S., Komarov V.A., Tronin O.A. Issledovanie sluchajny'x pogreshnostej spektral'no-vesovogo izmereniya parametrov signalov // Cifrovaya obrabotka signalov. 2011. № 4. S. 7–11.

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