Double-Cross-Correlation Processing for Blind Sampling-Rate and Time-Offset Estimation

2021 ◽  
pp. 1-1
Author(s):  
Aleksej Chinaev ◽  
Philipp Thuene ◽  
Gerald Enzner
Keyword(s):  
Cross Correlation ◽  
Sampling Rate ◽  
Correlation Processing ◽  
Time Offset ◽  
Blind Sampling ◽  
Double Cross

scholarly journals A New Cross-Correlation Algorithm Based on Distance for Improving Localization Accuracy of Partial Discharge in Cables Lines

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4549 ◽  
Author(s):  
Xianjie Rao ◽  
Kai Zhou ◽  
Yuan Li ◽  
Guangya Zhu ◽  
Pengfei Meng
Keyword(s):  
Cross Correlation ◽  
Partial Discharge ◽  
Effective Means ◽  
Sampling Rate ◽  
Propagation Distance ◽  
Test System ◽  
Computer Simulation Model ◽  
Localization Accuracy ◽  
Correlation Algorithm ◽  
Cable Lines

Locating the partial discharge (PD) source is one of the most effective means to locate local defects in power cable lines. The sampling rate and the frequency-dependent characteristic of phase velocity have an obvious influence on localization accuracy based on the times of arrival (TOA) evaluation algorithm. In this paper, we present a cross-correlation algorithm based on propagation distance to locate the PD source in cable lines. First, we introduce the basic principle of the cross-correlation function of propagation distance. Then we verify the proposed method through a computer simulation model and investigate the influences of propagation distance, sampling rate, and noise on localization accuracy. Finally, we perform PD location experiments on two 250 m 10 kV XLPE power cables using the oscillation wave test system. The simulation and experiment results indicate that compared with traditional TOA evaluation methods, the proposed method has superior locating precision.

scholarly journals Signal Processing for Parametric Acoustic Sources Applied to Underwater Communication

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5878
Author(s):  
María Campo-Valera ◽  
Ivan Felis-Enguix ◽  
Isidro Villó-Pérez
Keyword(s):  
Cross Correlation ◽  
Sound Propagation ◽  
Signal To Noise Ratio ◽  
Processing Technique ◽  
Underwater Communication ◽  
Carrier Wave ◽  
Acoustic Communications ◽  
Correlation Processing ◽  
Novel Processing ◽  
Special Relevance

For years, in the field of underwater acoustics, a line of research with special relevance for applications of environmental monitoring and maritime security has been developed that explores the possibilities of non-linear phenomena of sound propagation, especially referring to the so-called parametric effect or self-modulation. This article shows the results of using a new modulation technique based on sine-sweep signals, compared to classical modulations (FSK and PSK). For each of these modulations, a series of 16-bit strings of information with different frequencies and durations have been performed, with the same 200 kHz carrier wave. All of them have been tested in the Hydroacoustic Laboratory of the CTN and, through the application of cross-correlation processing, the limitations and improvements of this novel processing technique have been evaluated. This allows reaching better limits in discrimination of bits and signal-to-noise ratio used in underwater parametric acoustic communications.

scholarly journals Image Classification for Automated Image Cross-Correlation Applications in the Geosciences

2019 ◽  
Vol 9 (11) ◽  
pp. 2357 ◽  
Author(s):  
Niccolò Dematteis ◽  
Daniele Giordan ◽  
Paolo Allasia
Keyword(s):  
Cross Correlation ◽  
Earth Science ◽  
Operative Procedure ◽  
Support Vector ◽  
Diffuse Illumination ◽  
Monitoring Applications ◽  
Correlation Processing ◽  
Classification Of Images ◽  
Active Processes

In Earth Science, image cross-correlation (ICC) can be used to identify the evolution of active processes. However, this technology can be ineffective, because it is sometimes difficult to visualize certain phenomena, and surface roughness can cause shadows. In such instances, manual image selection is required to select images that are suitably illuminated, and in which visibility is adequate. This impedes the development of an autonomous system applied to ICC in monitoring applications. In this paper, the uncertainty introduced by the presence of shadows is quantitatively analysed, and a method suitable for ICC applications is proposed: The method automatically selects images, and is based on a supervised classification of images using the support vector machine. According to visual and illumination conditions, the images are divided into three classes: (i) No visibility, (ii) direct illumination and (iii) diffuse illumination. Images belonging to the diffuse illumination class are used in cross-correlation processing. Finally, an operative procedure is presented for applying the automated ICC processing chain in geoscience monitoring applications.

Identification and Cancellation of Pseudo Mode Function in EMD based on Energy Conservation

2016 ◽  
Vol 08 (01) ◽  
pp. 1650001 ◽  
Author(s):  
Dishan Huang ◽  
Xianglong Kong ◽  
Yibing Xia
Keyword(s):  
Experimental Data ◽  
Energy Conservation ◽  
Empirical Mode Decomposition ◽  
Cross Correlation ◽  
Sampling Rate ◽  
Processing Technique ◽  
Post Processing ◽  
Mode Function ◽  
Mode Decomposition ◽  
Signal Mode

This paper introduces an effective method to identify and cancel a pseudo mode function in empirical mode decomposition (EMD) under the condition of insufficient sampling rate. The contents of this paper have three aspects: First, basic properties of the pseudo mode are accurately revealed. Second, a post-processing technique for EMD is developed. This new technique, called as mode function cancellation, can identify and kick out the pseudo mode from the decomposition results, and correct the decomposition error in the intrinsic mode function. As a result, it can help us to improve the decomposition’s accuracy. Finally, for a mixing mode, the energy of pseudo mode function is proposed on the cross-correlation at time zero, and it can be used to measure the ratio of signal mode to pseudo mode. Examples and experimental data are illustrated to prove the validity of the presented approach. The research results show that this approach can improve EMD performance while a pseudo mode occurs in the decomposition.

A Combined Interpolation Method for Cross Correlation Based Particle Velocity Measurement

2012 ◽  
Vol 508 ◽  
pp. 67-70
Author(s):  
Gang Yang ◽  
Wei Dong Li ◽  
Yu Tao Wang ◽  
Ming Yu Li
Keyword(s):  
Correlation Function ◽  
Velocity Measurement ◽  
Cross Correlation ◽  
Interpolation Method ◽  
Sampling Rate ◽  
Time Delay Estimation ◽  
Parametric Models ◽  
Center Frequency ◽  
Estimation Accuracy ◽  
Particulate Solids

Cross correlation techniques have been proved to be a valuable tool for online continuous velocity measurement of particulate solids in pneumatic pipelines. In order to reduce computational complexity the sampling frequency is usually kept as low as possible, and the peak in the correlation function is found by interpolating the correlation function. Parabola functions are commonly used as parametric models of the cross correlation function in time delay estimation. However, the parabolic-fit interpolation method introduces a bias at low sampling rate to the center frequency ratio of input signal. In this paper, a combined interpolation method is proposed to improve the estimation accuracy. Experiments are carried out to evaluate the performance of the proposed interpolation method for low sampling rate. The experimental results have been promising and have shown the potential of the proposed method for particle flow velocity measurements.

Retrieving the Reflection events from passive signals

2020 ◽  
Author(s):  
Diako Hariri Naghadeh ◽  
Chris Bean
Keyword(s):  
Cross Correlation ◽  
Reference Signal ◽  
The Body ◽  
Body Waves ◽  
Estimation Methods ◽  
Wave Inversion ◽  
Correlation Processing ◽  
Processing Module ◽  
Ground Roll ◽  
Coherence Spectrum

<p>To create virtual shot gather from passive signals it is essential to cross-correlate all the signals with the reference trace. Since surface sources dominate the origin of seismic noise, the correlated sections are highly dominated by surface waves. If the target is surface wave inversion general cross-correlation will suit the target. But if the extraction of body waves from those signals is the main objective, coherent ground roll events mask the body waves making it difficult to extract them. To tackle this issue a frequency-spatial nonCoherent filter (FX-NCF) plus a post-correlation processing module are introduced. FX-NCF is a prediction filter and the filter operator is a function of frequency, station interval and the slope of the interested event. In the frequency domain, the filter is looking for the prediction of n-th trace coherence spectrum from the (n-1)-th signal’s coherence spectrum by minimizing the objective function. Hybrid norms used to minimize the error. The coherence spectrum of each trace is the coherency between the reference signal and the desired trace. Applying the FX-NCF on 2D real recorded passive signals shows its superiority over general cross-correlation, deconvolution interferometry, cross-coherence and multi-taper-method-coherence-estimation methods in highlighting surface and body waves also improving the signal-to-noise (S/N) ratio. To show the necessity of post correlation processing (before applying on real recorded signals) to highlight reflection events, hyperbolic Radon transform (HRT) as a suitable post-correlation module applied on correlated section due to applied FX-NCF on simulated passive signals from a simple 2D synthetic model. The result encouraged us to apply the same hybrid modules (FX-NCF plus HRT) on real recorded passive signals to reconstruct wanted reflection events.</p>

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