scholarly journals Determination of Propagation Times of Finite Ultrasonic Signals in the UFM Measuring Path

2021 ◽  
Vol 2096 (1) ◽  
pp. 012189
Author(s):  
S I Gerasimov ◽  
V D Glushnev ◽  
I N Zhelbakov
Keyword(s):  
Correlation Function ◽  
Cross Correlation ◽  
Correlation Method ◽  
Acoustic Signals ◽  
Sampling Frequency ◽  
Ultrasonic Signals ◽  
Frequency Sequence ◽  
Analytical Expressions ◽  
Crosscorrelation Function

Abstract This article provides a brief analysis of the error in calculating the discrete crosscorrelation function of the transit-time ultrasonic flowmeter signals. Special attention is paid to the study of the influence of the obtained discrete correlation function inaccuracy on the ultrasonic flowmeter’s propagation times determining error. It is known that for real time-limited acoustic signals, the discrete correlation function values are calculated with a significant error. The consequence of this is the appearance of the measurement error of the time delay between signals. The reason for this phenomenon is incorrect truncation of finite length digital sequences of the received acoustic signals. The report presents and describes an improved cross-correlation method for determining the time difference. The new algorithm takes into account the existing discretizing parameters of the received UPS – sampling frequency, sequence size and the truncated signal’s shape. Theoretical analytical expressions for the signals discrete cross-correlation function estimating are obtained as an approximation of a continuous function (the method of trapezoids and Simpson is used as an integral replacement). The numerical simulation by MatLab explains the error formation essence in the signal times difference calculating.

scholarly journals A Recursive Algorithm for Indoor Positioning Using Pulse-Echo Ultrasonic Signals

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5042
Author(s):  
Salvatore A. Pullano ◽  
Maria Giovanna Bianco ◽  
Davide C. Critello ◽  
Michele Menniti ◽  
Antonio La Gatta ◽  
...  
Keyword(s):  
Communication Systems ◽  
Polyvinylidene Fluoride ◽  
Cross Correlation ◽  
Recursive Algorithm ◽  
Low Frequency ◽  
Correlation Method ◽  
Experimental Results ◽  
Ultrasonic Signals ◽  
Average Improvement ◽  
Pulse Echo

Low frequency ultrasounds in air are widely used for real-time applications in short-range communication systems and environmental monitoring, in both structured and unstructured environments. One of the parameters widely evaluated in pulse-echo ultrasonic measurements is the time of flight (TOF), which can be evaluated with an increased accuracy and complexity by using different techniques. Hereafter, a nonstandard cross-correlation method is investigated for TOF estimations. The procedure, based on the use of template signals, was implemented to improve the accuracy of recursive TOF evaluations. Tests have been carried out through a couple of 60 kHz custom-designed polyvinylidene fluoride (PVDF) hemicylindrical ultrasonic transducers. The experimental results were then compared with the standard threshold and cross-correlation techniques for method validation and characterization. An average improvement of 30% and 19%, in terms of standard error (SE), was observed. Moreover, the experimental results evidenced an enhancement in repeatability of about 10% in the use of a recursive positioning system.

scholarly journals Determination of the rotational period of the comet 29P/Schwassmann-Wachmann-1 using dynamics of the dust structures (jets) in the coma

2012 ◽  
Vol 10 (H16) ◽  
pp. 176-176
Author(s):  
Aleksandra Ivanova ◽  
Viktor Afanasiev ◽  
Pavlo Korsun ◽  
Aleksandr Baransky ◽  
Maksim Andreev ◽  
...  
Keyword(s):  
Digital Filters ◽  
Cross Correlation ◽  
Rotation Period ◽  
Correlation Method ◽  
Photometric Data ◽  
Rotational Period ◽  
Water Ice ◽  
Ice Sublimation ◽  
Made In

AbstractWe present analysis of the photometric data of the distant comet 29P/Schwassmann-Wachmann-1, obtained at the 6-m BTA telescope (SAO RAS, Russia) and at the 2-meter telescope Zeiss-2000 (ICAMER, KB). The comet shows significant jets activity at large heliocentric distances, beyond the zone of water ice sublimation. Various digital filters were applied to increase the contrast of the jets and separate them. The rotation period of the nucleus was derived using cross-correlation method. The value of the rotation period is 12.1 ± 1.2 days for observations made in 2008 and 11.7 ± 1.5 days for observations made in 2009.

scholarly journals Determination of Broadening Functions using the Singular Value Decomposition (SVD) Technique

1999 ◽  
Vol 170 ◽  
pp. 82-90 ◽  
Author(s):  
Slavek Rucinski
Keyword(s):  
Correlation Function ◽  
Singular Value Decomposition ◽  
Cross Correlation ◽  
Singular Value ◽  
Spectral Lines ◽  
Linear Inversion ◽  
Standard Tool ◽  
Contact Binaries ◽  
Value Decomposition

AbstractThe cross-correlation function (CCF) has become the standard tool for extraction of radial-velocity and broadening information from high resolution spectra. It permits integration of information which is common to many spectral lines into one function which is easy to calculate, visualize and interpret. However, the CCF is not the best tool for many applications where it should be replaced by the proper broadening function (BF). Typical applications requiring use of BFs rather than CCFs involve finding locations of star spots, studies of projected shapes of highly distorted stars such as contact binaries (as no assumptions can be made about BF symmetry or even continuity) and [Fe/H] metallicity determinations (good baselines and avoidance of negative lobes are essential). It is stressed that the CCFs are not broadening functions. This note concentrates on the advantages of determining BFs through the process of linear inversion, preferably accomplished using the singular value decomposition (SVD). Some basic examples of numerical operations are given in the IDL programming language.

Research of Ultrasonic Distance Measurement System Based on Pseudo Random Digital Correlation

2014 ◽  
Vol 635-637 ◽  
pp. 733-737
Author(s):  
Yan Xing Qi
Keyword(s):  
Correlation Function ◽  
Measuring Equipment ◽  
Cross Correlation ◽  
Binary Sequence ◽  
Correlation Method ◽  
Absolute Error ◽  
Ultrasonic Signal ◽  
Measuring System ◽  
Echo Signal ◽  
Digital Correlation

An ultrasonic distance measuring system is designed by using MC9S12DG128 microcomputer in this paper. To improve the measuring distance and accuracy, the ultrasonic signal can be modulated with pseudo random binary sequence, and time of flight (TOF) can be determined by calculating the cross-correlation function of the transmission signal and its echo signal. What’s more, the two-step correlation method is adopted in order to reduce the computational complexity. The experiments show that absolute error of the measuring equipment is less than 5 millimeter within the range of 1-5 meter.

scholarly journals A novel method for quantifying periodicity and time delay in dynamic neural networks using unstable subaction potential threshold depolarizations

2020 ◽  
Vol 123 (3) ◽  
pp. 1236-1246
Author(s):  
Julian Sorensen ◽  
Nick J. Spencer
Keyword(s):  
Neural Networks ◽  
Correlation Function ◽  
Time Delay ◽  
Action Potentials ◽  
Cross Correlation ◽  
Time Lag ◽  
Cross Correlation Function ◽  
Electrical Signals ◽  
The Cross

Techniques to identify and correlate the propagation of electrical signals (like action potentials) along neural networks are well described, using multisite recordings. In these cases, the waveform of action potentials is usually relatively stable and discriminating relevant electrical signals straightforward. However, problems can arise when attempting to identify and correlate the propagation of signals when their waveforms are unstable (e.g., fluctuations in amplitude or time course). This makes correlation of the degree of synchronization and time lag between propagating electrical events across two or more recording sites problematic. Here, we present novel techniques for the determination of the periodicity of electrical signals at individual sites. When recording from two independent sites, we present novel analytical techniques for joint determination of periodicity and time delay. The techniques presented exploit properties of the cross-correlation function, rather than utilizing the time lag at which the cross-correlation function is maximized. The approach allows determination of directionality of the spread of excitation along a neural network based on measurements of the time delay between recording sites. This new method is particularly applicable to analysis of signals in other biological systems that have unstable characteristics in waveform that show dynamic variability. NEW & NOTEWORTHY The determination of frequency(s) at which two sources are synchronized, and relative time delay between them, is a fundamental problem for a wide a range of signal-processing applications. In this methodology paper, we present novel procedures for periodicity estimation for single time series and joint periodicity and time delay estimation for two time series. The methods use properties of the cross-correlation function rather than the cross-correlation function explicitly.

scholarly journals Emission-Line Variability in AGN

1989 ◽  
Vol 134 ◽  
pp. 100-102
Author(s):  
Dan Maoz
Keyword(s):  
Emission Line ◽  
Cross Correlation ◽  
Time Lag ◽  
Correlation Method ◽  
Seyfert Galaxy ◽  
Light Curves ◽  
Broad Line ◽  
Line Region ◽  
Order Of Magnitude

It has been apparent for some time that comparison of continuum and emission-line light curves of AGN may enable determination of the dimensions and structure of the Broad Line Region (BLR)(see Peterson 1988, and references therein). Observations to this end (Antonucci and Cohen 1983, Peterson et al. 1985, Clavel et al. 1987) and their analysis using cross-correlation to find the time lag between line and continuum variations (Gaskell and Sparke 1986), indicate BLR sizes an order of magnitude smaller than allowed by standard photoionization models for several AGN. Gaskell and Peterson (1987) analyzed errors in the cross-correlation method as applied to AGN time series in general and specifically to the Seyfert galaxy Akn120. In order to generalize and extend their analysis we investigated the significance of BLR sizes derived by cross-correlation under different model assumptions and observational circumstances (Maoz and Netzer 1988).

Cross-correlation method for determination of the profile of a single ultrashort pulse

1995 ◽  
Author(s):  
R. A. Avakian ◽  
A. E. Maylian ◽  
D. L. Hovannisian ◽  
A. O. Vardanian
Keyword(s):  
Ultrashort Pulse ◽  
Cross Correlation ◽  
Correlation Method
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