Wavelets and wideband correlation processing

1994 ◽  
Vol 11 (1) ◽  
pp. 13-32 ◽  
Author(s):  
L.G. Weiss
Keyword(s):  
Correlation Processing

scholarly journals About Using Two-Level Probing Signal in Nonlinear Radio Location

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
I.L. Afonin ◽  
◽  
A.N. Degtyaryov ◽  
A.L. Polyakov ◽  
V.G. Slyozkin ◽  
...  
Keyword(s):  
Block Diagram ◽  
Response Level ◽  
Noise Interference ◽  
Nonlinear Properties ◽  
Correlation Processing ◽  
Nonlinear Object ◽  
Probing Signal ◽  
Reflected Signal ◽  
The Difference ◽  
The Moment

A probing signal represented by two successive radio impulses having the same amplitude, but different energies is suggested for application in pulsed nonlinear radars, while for the receiver it is suggested to perform either correlation processing or optimal filtering of each of the reflected signal components at the carrier frequency. Due to the fact that the response of the optimal filter is proportional to the energy of the pulsed signal, the response levels of the two impulses reflected from an object lacking nonlinear properties will be equal. Should an object have nonlinear properties the response levels at the optimal processing device output at certain moments of time will be different thus indicating that a nonlinear object has been detected. Since the energies of the probing signal components are equal and optimal filtration is performed when receiving the reflected signal, this ensures that the noise interference equally affects the error while comparing levels of the received signal components. Depending on the error magnitude it is necessary to select upper and lower limits of the amplitude uncertainty within which response levels can be considered different. Decision about the presence of the nonlinear object is made if the difference in response levels goes beyond these limits. Suggested below is a block diagram of a decision-making device based on a successive correlation processing of each of the received signal components where the response level of the correlator at the moment when impulse ends is stored until the time when the decision is made i.e. when the second impulse ends.

scholarly journals Methods for mutual time delay estimation of wideband signals based on nonlinear digital filtering

2019 ◽  
Vol 30 ◽  
pp. 03008
Author(s):  
Roman Ershov ◽  
Oleg Morozov
Keyword(s):  
Time Delay ◽  
Communication Systems ◽  
Satellite Communication ◽  
Signal To Noise Ratio ◽  
Digital Filtering ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Wideband Signals ◽  
Correlation Processing

Methods for mutual time delay estimation of wideband signals propagating in satellite communication systems are proposed. The signals are propagated in different channels and received with low signal-to-noise ratio. A characteristic feature of satellite channel is the presence of the Doppler Effect, which leads to a shift and scaling the signal spectrums. The proposed approaches are based on the separation of narrow-band channels from the studied signals, using non-linear digital filtering algorithms in each channel, and subsequent optimal (correlation) processing. The accuracy of the proposed methods and the reliability of the determination of time delay are investigated.

scholarly journals Enhancing ambient noise correlation processing using vector sensors

2019 ◽  
Vol 145 (6) ◽  
pp. 3567-3577
Author(s):  
Brendan Nichols ◽  
James Martin ◽  
Christopher Verlinden ◽  
Karim G. Sabra
Keyword(s):  
Ambient Noise ◽  
Noise Correlation ◽  
Vector Sensors ◽  
Correlation Processing

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.

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