最新刊期
卷 ， 期 7 ， 1997
- 摘要：The condition of nonuniform sampling for Walter＇s sampling theorem and a kind of nonuniform sampling for Shannon sampling theorem are given in this paper. For the signal space spanned by compactly supported scaling function, nonuniform sampling theorem, which makes it possible to sample arbitrary compactly supported signal in the space is presented. Moreover,the advantages of nonuniform sampling for compactly supported wavelet space are given. In the end,the numerical examples show that theory presented in this paper is correct.关键词：Wavelet space;sampling theorem;nonuniform sampling;Compactly supported signal;scaling function2|181|4更新时间：2025-12-08
- 摘要：The problem of blind source separation of convolutive mixtures is considered in this paper. A class of criteria,which state sufficient conditions for indentification and separation,have been proved. Computationally efficient algorithms are also developed to implement these criteria. The validity of the criterion and the efficienCy of the algorithm are verified by simulations.关键词：blind identification;blind separation;Convolutive mixtures;Higher order spectrum2|269|36更新时间：2025-12-08
- 摘要：In this paper,a class of signals with AR noise which are invariable under autoregressive operator are discussed. By use of parameter separating and two-steps least-squares estimate methods,we directly give parameters estimation in AR noise and so in true signs. The method overcomes the difficulty that AR noise is unknown. The algorithm is linear and has fast computing speed and higher accuracy.关键词：不变类信号;AR噪声;参数估计2|36|0更新时间：2025-12-08
- 摘要：In this paper,a new technique of color image compression coding based on human vision, 3-D matrix transform compression coding,has been proposed. A mixed transform theory of3-D matrix and its accomplishment has been introduced to fully exploit spatial as well as spectral redundancies of the color image. Different from other transform coding methods, in which each component was compressed and encoded separately,it combined the intra and intercomponent compressions together. Simulution results demonstrate good quality reproduction and high compression ratio of this method.关键词：color image;compression coding;PSNR2|244|41更新时间：2025-12-08
- 摘要：An adaptive low bitrate vector quantization scheme for image compression is developed.The features of this scheme are: （1）Good adaptation is achieved due to a novel and effective prediction mechanism. （2）The efficiency of encoding the vector index is significantly improved by using dual addressing technique. （3）Simple implementation suitable for VLSI architecture.关键词：vector quantization;Image compression;adaptation;Dual addressing2|64|8更新时间：2025-12-08
- 摘要：篒n this paper，a novel efficient coding scheme is proposed as the newly developed fractal technique is applied to the sequence image coding．In order to improve thedecoded image quality，a new affine transform is also proposed．The contractlvlty condition is analyzed and the optimal parameters of the affine transform is derived in the paper．txperlmental results show that as for the international standard test sequence“Miss America”，the compression performance achieved is quite satisfied．关键词：分形;图像编码;仿射变换;序列图像编码2|103|28更新时间：2025-12-08
- 摘要：A method for estimating the parmeters of the vocal-tract area function from the first finite formants frequencies of speech signal is propsoed. An improved vocal-tract area function model is suggested based on the perturbation approach to the solution of the Webster＇s wave equation of the acoustic resonance tube by Schroeter. By considering the cross-influence of the different resonance modes of the perturbation,a cross-sensitivity perturbation relation in matrix form is presented. A method to measure the cross-sensitivity matrix is proposed. An iterative perturbation algorithm for determining the area function parameters from formant targets is developed. By looking up a ＇formant-to-perturbation ＇mapping codebook,an optimal initial perturbation vector for given formant targets is selected.A step-by-step sub-target perturbation procedure and adaptive factor for perturbation increment are adopted.An effective realizaion of the estmation of the vocal-tract area function is illustrated with comparison to the published data.关键词：speech signal processing;Speech synthesis;Low bit rate speech coding2|177|6更新时间：2025-12-08
- 摘要：In this paper,a new cost funcion is investigated and a new self-recovery equalization algorithm based on this function is proposed for Multi-Lecel QAM modulation. Tthis equalization algorithms based on the new algorithm are proposed. Analysis and computer simulations show that the convergence performanve and symbol error performance of the blind equlation algorithm are better than those of CMA algorithm,and are the same as those of the convertional LMS equalization algorithm. So these new equalization algorithms are very useful for practive use.关键词：Self-recovery equalization algorithm;Residual error;Symbol error performance2|174|27更新时间：2025-12-08
- 摘要：Experimental results on repeaterless 4× 622Mb/s × 200km, 2. 5Gb/s× 200km and 4. 354Gb/s （1× 2. 488Gb/s＋3 × 622Mb/s） × 160km conventional singlemode fiber transmission systems are reported in this paper. Results on another 4. 354Gb/s × 200km transmission with one repeater is also presented. Optical output from EDFA power booster is higher than 4dBm per channel （4 × 622Mb/s system）and 11dBm （2. 5Gb/s system）,respectively,while their frequency stability is better than 6 × 10-6 and 4.1× 10-6. Receiver sensitvity at the input of EDFA preamplifier reaches - 46. 8dBm （622Mb/s,NRZ 223 -1 PRBS）and - 39. sdBm （2. 5Gb/s,NRZ 223 -1 PRBS）. Bit-error rate of various channels is better than 4 × 10 124 ×10-15.关键词：optical fiber communication;WDM;EDFA2|42|1更新时间：2025-12-08
- 摘要：In this paper trellis-coded modulation（TCM）is applied to direct sequence spread spectrum multiple access （DS/SSMA）system over urban multipath fading channel. Based on the model of such a channel under DS conditions,we propose a new way which combines the theoretical analysis and numerical simulation to investigate the characteristics of TCM DS/SSMA systems and compare the performance of the DS/SSMA system with TCM of Ungerboeck＇s type and those of the systems with TCM of lower coding rate.关键词：Direct sequence spread spectrum multiple access;multipath fading;Trelliscoded modulation;Maximal likelihood decoding2|45|1更新时间：2025-12-08
- 摘要：In this paper,a new netWork topology,Bidirectional Double-Loop LAN which has both strong fault-tolerant ability and high communications efficiency,is introduced,together with its distributed reconfiguration algorithm whose functional principles and stability have been described and analyzed in detail.关键词：Local area network;fault-tolerance;reconfiguration;distributed algorithm;stability2|28|1更新时间：2025-12-08
- 摘要：This paper investgates th“bottleneck”problems about linear feed forward network classifiers （LFNC） for supervised learning. It is proved that some hidden layer in the LFNC with hidden node number less than the rank of the within dispersion matrix can do the Fisher linear transformation of the pattern samples from the previous layer,and the mechanism of producing bottleneck in the linear classifiers is disclosed and the method to solve it is presented. Finally,as an approach to capabilities of suth classifiers,it is propose applying the linear supervised classifiers to solving the inversion of nonsingular matrix. The computation results of two given examples show that the method to apply the linear supervised network to the inversion of nonsingular matrix is very effective.关键词：Feedforward neural networks;Linear classifier;Mean square classifier;Fisher linear discrimination;Inversing of matrix2|70|4更新时间：2025-12-08
- 摘要：A special kind of fuzzy associative memory system （FAM）-regularized fuzzy associative memory and its learning algorithm-regularization learning algorithm are presented. The regularized FAM has better performance than the FAMs designed by traditional methods, with lackage of and noise in training data exerting little influence on its performance. Finally,the application of the regularized FAM in fuzzy controller is illustrated with an example.关键词：regularization;Fuzzy associative memory;genetic algorithm;fuzzy controller2|32|6更新时间：2025-12-08
- 摘要：In this paper,a kind of real-time speech coder with high quality and low complexity at the bit rate of 8kb/s is presented. The encoding algorithm is based on algebraic code excited linear prediction （ACELP）. Efficient codebook structure and codebook search strategies, along with efficient vector quantization procedures,have been developed to achieve high quality reconstructed speech while maintaining low complexity. Without any external RAM or ROM,the algorithm has been implemented on TMS320C50 for a realtime full duplex communication system.Through performance tests of SNR and subjective listening,we have verified that the proposed algorithm is better than the 8kb/s VSELP algorithm and its complexity is almost the same as that of VSELP algorithm.关键词：Algebraic code excited linear prediction （ACELP）;Vector quantization （VQ）;Real-time realization2|67|5更新时间：2025-12-08
- 摘要：The paper investigates the effect of interframe spectral dependence in speech on the recognition accuracy of HMM-based speech recognition systems. It is proposed that the Markov chain model （MCM）may be used to account for the spectral dependence between frames.Experiments on isolated word recognition have shown that using the MCM as a complement to the HMM in recognition can achieve improved recognition approximately by 16 percentage points as compared to HAM-based systems.关键词：Speech recognition;Hidden Markov models;Hybrid models2|50|2更新时间：2025-12-08
- 摘要：This paper presents a new digital audio coding method based on optimized adaptive wavelet selection and wavelet coefficients quantization procedure,which are developed with the results from psycho acoustic model of masking in human hearing to minimize the number of bits allocated To each frame without perceptual distortion. In addition,the dynamic codebook is adopted to get rid of statistical redundancy. Experiments indicate that the algorithm achieves transparent audio coding of monophonic CD quality at 64 kbps or so.关键词：audio coding;Compactly supported orthogonal wavelet bases;optimization;Psycho-acoustic model;Dynamic bits allocation2|93|0更新时间：2025-12-08
- 摘要：Motion compensation is key technique for image sequence coding. This paper reports an improved motion estimation method by considering the homogeneity of motion fields.Comparing with the results of MPEG-I, 1530% bit rate reduction can be obtained with the same quality of picture.关键词：motion compensation;Homogeneous field;Moving image coding2|33|0更新时间：2025-12-08
- 摘要：In this paper,the optimum nonlinearity Robust-M detection of random signals in m-dependent noise is obtained. Simulation example show that this detection is a well Robust detection.关键词：m-dependent sequence;Robust-M detection;Optimum nonlinearity2|25|3更新时间：2025-12-08
- 摘要：A new lincompex method is proposed,it is not only according to the traditional lincompex in HF communication system but also the techniques of the digital processing of speech signals. Because the digital signal processing is its prime part and the modulation of frequency coding is used,it is more feasible than the traditional lincompex and the result is satisfactory at the same time.关键词：Lincompex;Frequency coding;HF communication2|47|2更新时间：2025-12-08
- 摘要：Prechirp technique has been proposed as a method to compensate dispersion of optical fiber. This paper analyzes the transient chirp in this technique in detail and gets a conclusion that it will cause energy penalty. At last we recommend a method using optimal delay to get rid of this influence,and this delay is calculated with different parameters.关键词：optical fiber communication;Prechirp;chirp;dispersion compensation2|61|1更新时间：2025-12-08
- 摘要：This paper presents an approach to realize finite precision chaotic systems via perturbation of m-sequences. Several properties of the chaotic signal are studied under different perturbation parameters （i. e. period,amplitude and distribution）. It is shown that the order of m-sequence is determined by the period of the desired chaotic signal,and the perturbation bit number can be calculated from the maximal differential of the chaotic system. When the precision increases,the perturbation amplitude decreases exponentially.关键词：m-sequence;Finite precision effect;Invariant distribution;Perturbation2|475|215更新时间：2025-12-08
- 摘要：The chaotic phenomena of the sample PLL frequency sythesizer have been studied in this paper. The phase-locus diagrams of chaotic attractor and bifurcation diagrams are given.The parameter ranges where chaos exist are also obtained by numerical computation.关键词：chaos;SPLL;Chaotic attractor;bifurcation2|57|5更新时间：2025-12-08
- 摘要：This paper is to study the validity of the G-diagnosis algorithm that has been regarded as a classical algorithm for faulty diagnosis in analog circuits. The results of this study indicate that: （1）wrong mathematical models are used to estimate G-parameters ; （2）the estimated Gparameters must be biased against actual G-parameters;（3）the G-algorithm will give mistaken diagnosis conclusions if harsh conditions can not be satisfied. The paper proposes formulas,which are easily calcuated with nominal data of circuits,to forecast if the G-diagnosis algorithm can locate faults correctly or not.关键词：fault diagnosis;parameter estimation;Analog circuits;model2|28|1更新时间：2025-12-08
- 摘要：In this paper, blind equalication techniques based on maximizing the aposteriori probability density function （p. d. f） are investigated and a novel soft Decision directed is proposed. The new algorithm can achieve the faste convergence speed and smaller residual ISI. The blind decision feedback equalizer（DFE） using soft DD algorithm is also presented,its performance is superior to that of linear equalizer （LE）. Finally,in order to guarantee the covergence of the new algorithm,the approximate iterative algorithm for the variance of the convolutional noise is proposed. Simulation results confirm the effectiveness of the proposed techniques on various channels and QAM signals.关键词：Blind equalization;Soft Decision-directed;A-posteriori probability density function （p. d. f）;Convolutional noise2|162|4更新时间：2025-12-08
- 摘要：Classification trees and multilayer feed forward neural networks are two popular approaches to the pattern recognition problem. In this paper,a new pattern classification way based on neural treeis presented. This approach uses some small scale neural networks as the nodes of the classification tree to extract the nonlinear features of patterns. The experiment results have shown that this approach can decrease the error rate of pattern recognition and the number of nodes of classification tree,also can shorter the training time of neural network.关键词：neural network;pattern recognition;feature extraction;classification tree2|72|2更新时间：2025-12-08
- 摘要：This paper investegates evolution strategies of genetic algorithms. A kind of adaptive evolution strategies of genetic algorithms is presented, which combines basic genetic algorithms with local search scheme in genetic operation level and tunes the evolution strategies of genetic algorithms adaptively and controls the pressure of local search based on the genetic environment parameters. Its real implementation methods for TSP and the experiment results are introduced.关键词：genetic algorithms;Adaptive Evolution Strategies;TSP;Local Search2|426|50更新时间：2025-12-08
- 摘要：It is an open problem how the correlation-immunity functions over rings ZN are characterzed by the spectral technique. The problem is solved in this paper.关键词：Correlation-immunity;Orthogonal array;Spectrum2|42|1更新时间：2025-12-08
- 摘要：Basing on the theorem for decoding Justesen＇s algebraic gecometry codes by X.Chen,a algorithm of decoding Justesen elliptic codes is obtained. This decoding algorithm can decode any Justesen elliptic code up to the true minimum distance.关键词：Gr o buer bases;Algebraic geometric codes;decoding;Elliptic codes;minimum distance2|48|0更新时间：2025-12-08
- 摘要：The Banyan network is a kind of multistage interconnection networks （MINs） and is widly used as a building block in ATM switch fabric designs. The neural network controlled Banyan networks have been proposed in some papers but its hardward implementation is complicated. In this paper we propose a new neural network controlled Banyan network with input-output-queueing. Its neural network controller is easy to implement. Our simulation results show that this mathod is very efficient. Here,we give its hardware implementation.关键词：ATM;queueing;switching;neural network;Scheduling.2|67|4更新时间：2025-12-08
- 摘要：基于强Ｕｎｉｖｅｒｓａｌ２函数的消息认证码构造与安全性分析ＴｈｅＣｏｎｓｔｒｕｃｔｉｏｎａｎｄＳｅｃｕｒｉｔｙＡｎａｌｙｓｉｓｏｆＭｅｓｓａｇｅＡｕｔｈｅｎｔｉｃａｔｉｏｎＣｏｄｅＢａｓｅｄｏｎＳｔｒｏｎｇＵｎｉｖｅｒｓａｌ２Ｆｕｎｃｔｉｏｎ￥朱华...2|39|1更新时间：2025-12-08
- 摘要：一种ＡＴＭ交换机的设计与实现ＴｈｅＤｅｓｉｇｎａｎｄｌｍｐｌｅｍｅｎｔａｔｉｏｎｏｆａＳｈａｒｅｄＢｕｆｆｅｒＡＴＭｓｗｉｔｃｈ￥／／赵豫彪，刘增基（西安电子科技大学综合业务网国家重点实验室，西安７１００７１）本文介绍国家８６３计划中８×８ＡＴＭ交换...2|38|0更新时间：2025-12-08
- 摘要：一个新的二进制线性分组码的维数上限ＡＮｅｗＤｉｍｅｎｓｉｏｎＢｏｕｎｄｆｏｒＢｉｎａｒｙＬｉｎｅａｒＢｌｏｃｋＣｏｄｅｓ￥／／马啸，王新梅（西安电子科技大学１０６信箱，西安７１００７１）本文仅限于讨论二进制的情形，所用方法可以推广到多进制情形．用［ｎ...2|56|0更新时间：2025-12-08
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