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Table of Contents
CAT-7 Cable Evaluation for Square Kilometre Array Analogue Signal Transport
Identifying Opportunities for Deterministic Network Coding in Wireless Mesh Networks
Mitigation of Atmospheric Turbulence Distortions in Long Range Video Surveillance
CAT-7 Cable Evaluation for Square Kilometre Array Analogue Signal Transport by P.K. Langat, P. van der Merwe, T. Ikin and H.C. Reader
Abstract: Data-cable systems are essential for an evolving Square Kilometre Array (SKA) phasedarray demonstrator project. Loss, dispersion and channel coupling are the characteristics of interest. We evaluate a Category 7 (CAT-7) cable system, which incorporates a 20 m CAT-7 cable, balun transformers, and ARJ45 connectors. Measurements from 30 MHz - 1.5 GHz are made using a calibrated Vector Network Analyzer (VNA). Through, Reflect, Line (TRL) as well as Short, Open, matched Load, Through (SOLT) calibration techniques were performed, which separately test the cables and the entire system performance respectively. A further measurement isolates the baluns. The connectors and baluns are mounted on customised printed circuit boards. We investigated phase dispersion, return loss, attenuation, near-end crosstalk (NEXT) and far-end crosstalk (FEXT). The best system was found to have a linear phase response in the 30 MHz to 1.4 GHz band, with NEXT and FEXT levels below -50 dB and -63 dB respectively. Such performance makes this cable class a candidate for high-volume data streams anticipated for the SKA.
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Identifying Opportunities for Deterministic Network Coding in Wireless Mesh Networks by M.J. Grobler and A.S.J. Helberg
Abstract: Recent advances in methods to improve network utilisation has lead to the introduction of Network Coding, a technique that can reduce local congestion in a network by combining information sent over the network. In this paper the use of deterministic Network Coding in a Wireless Mesh Network (WMN) is proposed. A method to determine where Network Coding can be implemented in a WMN is presented. It is shown that the inherent properties of WMNs provide good opportunities for the implementation of this method.
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Mitigation of Atmospheric Turbulence Distortions in Long Range Video Surveillance by P.E. Robinson and W.A. Clarke
Abstract: This paper explores the problem of atmospheric turbulence in long range video surveillance. This turbulence causes a phenomenon called heat scintillation or heat shimmer which introduces distortions into the video being captured. The nature of these distortions is discussed and a number of possible solutions explored. Using these solutions, three algorithms are implemented to attempt to mitigate the effects of heat shimmer. Within this field there is very little subject matter on the topic of objectively comparing the performance of heat shimmer reduction algorithms. A set of possible metrics is proposed in this paper and used to compare the performance of the implemented algorithms. These results provide insight into the nature of the algorithms and the effectiveness of the metrics under consideration.
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