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Proceedings of the 1992 South African Symposium on Communications and Signal Processing最新文献

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A new PCM codec test method with reduced real-time and signal processing requirements 一种新的PCM编解码器测试方法，降低了实时性和信号处理要求
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274307
H. Hanrahan, B. Cronje, I. Riphagen
{"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}
引用次数: 0
Efficient complex demodulation by correctly packing ADC data 通过正确封装ADC数据，实现高效的复杂解调
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274300
J. G. Lourens
{"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}
引用次数: 0
Modelling of frequency hopped VHF channels in an urban environment and error correction on the channel 城市环境下VHF跳频信道建模及信道误差校正
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274286
A. V. van Heerden, H. C. Ferreira
{"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}
引用次数: 4
Band pass line codes 带通线路码
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274308
L. Fouche, L. Botha, H. Ferreira
{"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}
引用次数: 1
Applying a transient suppression technique to emulate frequency hopping in channel simulators 应用瞬态抑制技术模拟信道模拟器中的跳频
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274285
A.P.R. Opperman, L. Linde
{"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}
引用次数: 0
Radar target recognition using multiple bounce scattering terms 基于多重弹跳散射项的雷达目标识别
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274320
J. Spoelstra, E. Botha
{"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}
引用次数: 2
Estimating acoustic attenuation of chirp sonar signals for marine sediment classification: comparison of matched filtering and spectral-shift techniques 估计啁啾声呐信号的声衰减用于海洋沉积物分类:匹配滤波和频谱移位技术的比较
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274301
D. Claassen, J. G. Lourens
{"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}
引用次数: 0
A technique for automatically segmenting images of the surface froth structures that are prevalent in industrial flotation cells 一种自动分割工业浮选池表面泡沫结构图像的技术
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274302
P. Symonds, G. de Jager
{"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}
引用次数: 20
Omni-font character recognition using templates and neural networks 全字体字符识别使用模板和神经网络
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274275
S. Mostert, J.A. Brand
{"title":"Omni-font character recognition using templates and neural networks","authors":"S. Mostert, J.A. Brand","doi":"10.1109/COMSIG.1992.274275","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274275","url":null,"abstract":"With regard to facsimile graphic pages, routines to extract character images from within the page are implemented. Methods to trace joinings in closely spaced letters are discussed. Preprocessing of the extracted image by skeleton extraction (using average area) is implemented to remove font specific factors such as bold and line thickening. After specification of the reduced image size required, the image is compressed with the necessary amount by a pixel averaging and overlapping routine for better context sensitivity. The reduced images are used to train multiple MLP neural networks each for a single font using the back propagation training algorithm. The outputs of the networks are combined to form a maximum likelihood search for the best match. Results close to 100% are obtainable.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"3 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":"115365706","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}
引用次数: 0
A cost effective fingerprint verification algorithm for commercial applications 一种适用于商业应用的低成本指纹验证算法
Proceedings of the 1992 South African Symposium on Communications and Signal Processing Pub Date : 1992-09-11 DOI: 10.1109/COMSIG.1992.274304
D. Weber
{"title":"A cost effective fingerprint verification algorithm for commercial applications","authors":"D. Weber","doi":"10.1109/COMSIG.1992.274304","DOIUrl":"https://doi.org/10.1109/COMSIG.1992.274304","url":null,"abstract":"The print is scanned in and enhanced using a 2 dimensional filter which is implemented using a 2D Fourier transform. The image is then thresholded to a binary image. The fingerprint ridges are simultaneously thinned and traced by a line-following technique to obtain a skeletonised image. During this process, the positions of certain types of minutiae are detected. These minutiae are then compared to a previously stored template to verify the identity of the user. The template matching procedure is robust against translation and rotation of the fingerprint.<<ETX>>","PeriodicalId":342857,"journal":{"name":"Proceedings of the 1992 South African Symposium on Communications and Signal Processing","volume":"595 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":"122726616","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}
引用次数: 21
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