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Algorithms for self-synchronizing ciphers 自同步密码算法
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49321
G. Kuhn
{"title":"Algorithms for self-synchronizing ciphers","authors":"G. Kuhn","doi":"10.1109/COMSIG.1988.49321","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49321","url":null,"abstract":"Necessary conditions are determined for a self-synchronizing steam cipher algorithm to be secure. The stream cipher encryption hardware considered consists of a keystream generator, an exclusive-OR gate to combine the keystream and the binary coded message stream, and circuits to establish initial cryptographic synchronization. The security of the system is based on the use of secret cryptographic keys which must be transmitted to the receiver in advance over a secure route. It is shown that the algorithm (when expressed as a logic function) should be correlation-immune, permutation-immune, and nonlinear in its arguments. An example of a 125-stage 7th-order correlation-immune function is given, and its resistance to cryptanalysis is evaluated.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125688691","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: 9
A new linear phase, robust, non-linear smoothing method for stationary and non-stationary time or space series data 一种新的线性相位，鲁棒，非线性平滑方法，用于平稳和非平稳时间或空间序列数据
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49310
M. Hattingh
{"title":"A new linear phase, robust, non-linear smoothing method for stationary and non-stationary time or space series data","authors":"M. Hattingh","doi":"10.1109/COMSIG.1988.49310","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49310","url":null,"abstract":"A description is given of a linear-phase robust nonlinear smoothing method (the LRNS method) that can be used to smooth any time-series or space-series data to any degree. After a short review of existing smoothing methods, the drift removal method is discussed, its limitations are shown, and a step-by-step description is given how they are overcome in the proposed LRNS method. Examples are used to demonstrate the effectiveness of this method in smoothing synthetic and real data. With the LRNS method, the degree of smoothing is controlled by choosing only one parameter; any data series can be smoothed, whether it is regularly or irregularly sampled, contains spikes, random noise or missing data; only one weight is used this weight automatically adapts with changes in the data. Efficiency and stability are unaffected by the degree of smoothing, and no amplitude overshooting occurs. The method's greatest benefit lies in its simplicity rival those of 'smoothing by eye' without its bias and subjectivity.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130558571","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
Automatic speaker independent alignment of continuous speech with its phonetic transcription using a hidden Markov model 使用隐马尔可夫模型对连续语音进行语音转录的自动独立校准
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49298
J. Brummer, M.W. Boetzer
{"title":"Automatic speaker independent alignment of continuous speech with its phonetic transcription using a hidden Markov model","authors":"J. Brummer, M.W. Boetzer","doi":"10.1109/COMSIG.1988.49298","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49298","url":null,"abstract":"A way is presented to time-aligned phonetic transcriptions with an acoustic speech waveform using hidden Markov models defined by the transcriptions. Given an utterance of speech and its phonetic transcription, the algorithm will yield the starting and ending times of all the phonemes in the transcription, relative to the start of the utterance. The probabilities for the model are obtained from phoneme duration probabilities and feature probabilities for a few coarse phoneme classes. Because of the coarse classes, the method is speaker-independent. The alignment is accomplished using the Viterbi algorithm. An efficient way of implementing the Viterbi algorithm is given. By using single word transcriptions, the method can be used to detect words in continuous speech, which allows words to be searched for using only their phonetic representations. Two different hidden Markov models (HMM) were used, one with discrete observation symbols and one with continuous observation vectors. The continuous model works better, but the discrete one works faster.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129978188","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
The SABC's TV/radio satellite distribution system SABC的电视/广播卫星分配系统
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49301
D. Conradie
{"title":"The SABC's TV/radio satellite distribution system","authors":"D. Conradie","doi":"10.1109/COMSIG.1988.49301","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49301","url":null,"abstract":"During 1986, the South African Broadcasting Corporation (SABC) implemented a system for distributing its TVI program and various radio programs via a leased transponder on an Intelsat satellite to distant terrestrial transmitting stations for rebroadcasting purposes. The system and its performance are described. A brief description of the B-MAC (B version of the multiplexed analogue components system) coding format is included. Problems experienced during the first two years of operation and the solutions applied are discussed, as well as the overall successes of the system. Problems considered are: the potential existence of interference from terrestrial microwave links, rain attenuation, lightning damage to equipment, synchronization problems between B-MAC and asynchronous video signals, cross polarization effects, and satellite tracking/stationkeeping.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131398006","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
Final results of the development of a 2400 b/s LPC vocoder 最终研制出一个2400 b/s的LPC声码器
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49297
D.J. Joubert, J.J.D. van Schalkwyk
{"title":"Final results of the development of a 2400 b/s LPC vocoder","authors":"D.J. Joubert, J.J.D. van Schalkwyk","doi":"10.1109/COMSIG.1988.49297","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49297","url":null,"abstract":"The final results obtained from a TMS 32010-based 2400 b/s linear-predictive coding (LPC) vocoder system are described. The design used as well as practical considerations and problems associated with the preprocessing and pitch prediction are discussed. The results of intelligibility tests, performed with phonetically balanced word lists, are also described. The good results obtained with the system are due mainly to the large dynamic range of the input stage, as well as the judicious choice of algorithms and the accurate implementation thereof.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"7 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120860669","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 computer search for convolutional codes with good distance profiles 用计算机搜索具有良好距离轮廓的卷积代码
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49319
H. Ferreira, D. A. Wright, I. S. Shaw, C. R. Wyman
{"title":"A computer search for convolutional codes with good distance profiles","authors":"H. Ferreira, D. A. Wright, I. S. Shaw, C. R. Wyman","doi":"10.1109/COMSIG.1988.49319","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49319","url":null,"abstract":"A nested step-by-step computer search was undertaken to find new convolutional codes with good distance profiles and information rates R=k/n, where the information symbols k and the n codeword symbols are: 4<or=n<or=8, 2<or=k<or=n-2. These codes are intended for sequential decoding. The search was set up in such a way that information about the weight distributions of all code sequences, or a truncated version of this weight distribution, was available after each step. The algorithm used processes all retained information sequences at each step, but bounds the computational work by not storing any information about an information sequence once its encoded weight exceeds a target minimum weight which is specified at the beginning of the search. If an information sequence is thus deleted at a given step of the search, it is not processed at the next or any further steps to evaluate the next connection vector or any further sets of connection vectors. Although the search will eventually run on a Cray supercomputer, it was conducted using an IBM PC. The new codes are summarized in tabular form.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129471073","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
Path length analyzer for digital microwave radio 数字式微波无线电路长分析仪
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49317
D. Gale, R. Braun
{"title":"Path length analyzer for digital microwave radio","authors":"D. Gale, R. Braun","doi":"10.1109/COMSIG.1988.49317","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49317","url":null,"abstract":"An instrument is proposed that would use the tellurometer technique of T.L. Wadley (1958) to analyze the electrical length as opposed to the physical length of a microwave radio's propagation path. The instrument can be used by the line-of-sight radio-link engineer to assess such factors as stable and turbulent atmospheric multipath, reflections from elevated ground layers, reflections from atmospheric sheets, reflections from ground or water, reflections due to inverse bending and ducting. The full extent of the usefulness of the instrument has not yet been investigated. A practical example of the analysis of the ground reflection is given. Time-domain analysis is suggested for analyzing paths under test.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133510624","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
A design approach for real-time signal processing software 一种实时信号处理软件的设计方法
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49304
H. Schulz, J. A. Marks
{"title":"A design approach for real-time signal processing software","authors":"H. Schulz, J. A. Marks","doi":"10.1109/COMSIG.1988.49304","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49304","url":null,"abstract":"The process-resource approach to system software design is described and illustrated using a simple finite-impulse response filter design example. Process-resource design is essentially an object-oriented system design approach, i.e. the system is viewed as a collection of concurrent activities called objects. The system is decomposed into processes and resources using data flow analysis techniques. Resources 'source' and 'sink' data to and from processes, respectively. Processes initiate data flow transactions to and from resources and process the data. Most resources are passive and respond to initiatives from the processes. After defining the functional specification of a system from a user requirement, a data flow analysis is performed. The first-level system analysis follows directly from the functional specification. After the processes, resources and their operations are specified and designed, coding can begin. The approach is iterative, progressively describing the system in greater detail. This enables the designer to break the system down into manageable entities and simplifies project management. The initial overhead in the earlier design stages pays for itself in the end, as it leads to well-structured, reliable and reusable software.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116909390","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
Realtime implementation of a subband coder using CQF filters 使用CQF滤波器的子带编码器的实时实现
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49296
E.H.S. Shearer, T. Barnwell
{"title":"Realtime implementation of a subband coder using CQF filters","authors":"E.H.S. Shearer, T. Barnwell","doi":"10.1109/COMSIG.1988.49296","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49296","url":null,"abstract":"The coder described uses a full-duplex, five-octave-band structure. An additional splitter is used to discard the top half of the highest band, allowing significant data reduction with little loss in quality. Conjugate quadrature filters (CQFs) were chosen for this implementation because they exhibit perfect reconstruction and were expected to offer better performance than simple quadrature mirror filters (QMFs). Adaptive pulse-code modulation (APCM) coders are used to quantize and code each band. The number of levels in the APCM coder is a parameter of the implementation, so the realization can be easily configured to operate at data rates from 10 kb/s to 24 kb/s. Results indicate that the speech quality of the CQF implementation was barely discernible from that of a QMF-based implementation. The basic building block used in the subband coder is the two-band analysis/reconstruction system. The analysis section uses high and low pass filters to split the speech into two bands. Each subband signal is then decimated to its nominal Nyquist rate, thus preserving the total number of samples in the signals to be coded. The reconstruction section inserts zeros into the sample streams and interpolates them using the corresponding reconstruction filters.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121198332","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
Real time speech classification and pitch detection 实时语音分类和音高检测
COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings Pub Date : 1988-06-24 DOI: 10.1109/COMSIG.1988.49291
J. A. Marks
{"title":"Real time speech classification and pitch detection","authors":"J. A. Marks","doi":"10.1109/COMSIG.1988.49291","DOIUrl":"https://doi.org/10.1109/COMSIG.1988.49291","url":null,"abstract":"An accurate silence-unvoiced-voiced classification and pitch detection algorithm is described and its implementation for real-time applications on a Texas Instruments TMS320C25 digital signal processor is evaluated. Speech classification is separated into silence detection and voice-unvoiced classification. Only the signal's energy level and zero-crossing rate are used in both classification processes. Pitch detection need only operate on voiced periods of speech. A peak picking technique is used to successively home in on the peaks that bound the pitch periods. Tests are performed on the found peaks to ensure that they are pitch-period peaks. A real-time implementation strategy is developed that combines silence detection with the signal acquisition and tightly couples voiced-unvoiced classification with pitch detection. The silence detection task is interrupt-driven and the pitch detection task loops continuously. The execution speed and accuracy results for this algorithm are shown to compare favorably with those for other such algorithms published in the literature.<<ETX>>","PeriodicalId":339020,"journal":{"name":"COMSIG 88@m_Southern African Conference on Communications and Signal Processing. Proceedings","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129292014","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: 15
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