{"title":"A new PCM codec test method with reduced real-time and signal processing requirements","authors":"H. Hanrahan, B. Cronje, I. Riphagen","doi":"10.1109/COMSIG.1992.274307","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274307","url":null,"abstract":"A new test method is described which allows full gain and SNR curves to be measured within 2s with better than 0.1 dB signal level spacing. A transposed test configuration avoids the need for analog test signal generation. An exponentially windowed tone is the test signal. The entire gain and SNR versus signal level curves are derived from one stimulation. Reference curves for the new test signal for A-Law codecs resemble smoothed versions of those of CCITT Method 2.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114755004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Efficient complex demodulation by correctly packing ADC data","authors":"J. G. Lourens","doi":"10.1109/COMSIG.1992.274300","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274300","url":null,"abstract":"This paper describes a data handling process which in effect implements complex demodulation of signals to baseband in a numerically efficient manner. Two ways of understanding the process are described, and the numeric efficiency is discussed.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129954273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modelling of frequency hopped VHF channels in an urban environment and error correction on the channel","authors":"A. V. van Heerden, H. C. Ferreira","doi":"10.1109/COMSIG.1992.274286","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274286","url":null,"abstract":"Experimental and analytical results of applying Fritchman partitioned Markov chains to model the error sequences of mobile and stationary channels are obtained from real-time measurements. The Markov chain channel models were applied to the system using four modulation schemes, namely FSK, DPSK, QPSK and 8-ary PSK. Using error distributions obtained from both the experimental measurements and the channel models, BCH and Reed-Solomon error correcting codes of various block lengths and information rates are investigated. The effect of different interleaving depths on the block error rate is shown.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117180150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Band pass line codes","authors":"L. Fouche, L. Botha, H. Ferreira","doi":"10.1109/COMSIG.1992.274308","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274308","url":null,"abstract":"This paper considers block codes and finite state machine codes with higher-order spectral zeros at DC for use where a speech channel and data are transmitted on the same twisted pair. The use of these codes is proposed for the asymmetrical digital subscriber line and the South African Diginet system.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"236 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121066782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Applying a transient suppression technique to emulate frequency hopping in channel simulators","authors":"A.P.R. Opperman, L. Linde","doi":"10.1109/COMSIG.1992.274285","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274285","url":null,"abstract":"A transient suppression technique is presented for use in channel simulators with very low fading rates. This transient, caused by the lack of an input sequence before k=0, is eliminated by specification of the initial conditions of the filter to cause a stationary output at k=0. This simple but effective technique is used to incorporate random frequency hopping in an existing fading channel simulator.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131837563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Estimating acoustic attenuation of chirp sonar signals for marine sediment classification: comparison of matched filtering and spectral-shift techniques","authors":"D. Claassen, J. G. Lourens","doi":"10.1109/COMSIG.1992.274301","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274301","url":null,"abstract":"Two methods of estimating the attenuation are compared by numerical simulation. It is found that the instantaneous frequency method, a spectral-shift technique, yields better results in a noisy environment than the matched filtering method, which is a correlation method. The instantaneous frequency method is applied to real data and the results are discussed.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124839968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Radar target recognition using multiple bounce scattering terms","authors":"J. Spoelstra, E. Botha","doi":"10.1109/COMSIG.1992.274320","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274320","url":null,"abstract":"One of the most successful approaches to radar target recognition is based on the down-range radar cross section profile in which some peaks relate to interactions between structures as opposed to direct specular scattering. The authors propose a new method using interaction (multiple bounce) terms to compute a truly rotation invariant feature for radar targets to be used for recognition.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115459801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A technique for automatically segmenting images of the surface froth structures that are prevalent in industrial flotation cells","authors":"P. Symonds, G. de Jager","doi":"10.1109/COMSIG.1992.274302","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274302","url":null,"abstract":"The froth structures convey considerable visual information on cell performance, particularly in terms of grade and recovery. Fundamental to the design of a machine vision system for monitoring the operation is the ability to identify and extract those visual features that are descriptive of the surface froth. The individual bubbles give rise to complex 3-dimensional structures that are problematic to segment accurately and reliably. This paper briefly discusses the classical segmentation of surface froth images and then presents a morphological image processing technique that is capable of segmenting surface froth images accurately and reliably.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133608346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Neural network recognition of magnetic ink code line using magnetically sensed time variant signal","authors":"S. Mostert, J. J. van Rensburg, N. Goosen","doi":"10.1109/COMSIG.1992.274274","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274274","url":null,"abstract":"This paper provides a solution unique in that the speed varies with the person swiping the check past the head, and the recognition is made without any additional timing information. Techniques applied and researched vary from neural networks to various heuristics based on the properties of the signal derived from the magnetic sense head. The neural network recognition is explored in more detail to find the most optimal solution.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123339361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A survey of point pattern matching techniques and a new approach to point pattern recognition","authors":"G. Cox, G. de Jager","doi":"10.1109/COMSIG.1992.274276","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274276","url":null,"abstract":"The new technique developed by the authors is invariant to rotational, scaling and translational transformations, and is optionally reflection invariant. The techniques presented are compared, and specific applications described.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123531410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}