IEEE Transactions on Information Theory

Volume 20 Issue 3 • May 1974

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Displaying Results 1 - 25 of 27
  • Practical applications of coding

    Publication Year: 1974, Page(s):305 - 310
    Cited by:  Papers (32)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (934 KB)

    Coding applications have grown rapidly in the past several years with cost-effective performance demonstrated on several channels. Convolutional coding with soft-decision Viterbi decoding has emerged as a standard technique and is particularly well adapted to the commnnication satellite channel. Decoder implementations are discussed and examples are cited. Robustness of code performance is emphasi... View full abstract»

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  • An upper bound to the capacity of the band-limited Gaussian autoregressive channel with noiseless feedback

    Publication Year: 1974, Page(s):311 - 316
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (605 KB)

    Upper bounds to the capacity of band-limited Gaussian<tex>m</tex>th-order autoregressive channels with feedback and average energy constraint<tex>E</tex>are derived. These are the only known hounds on one- and two-way autoregressive channels of order greater than one. They are the tightest known for the first-order case. In this case let<tex>\alpha_1</tex>be the... View full abstract»

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  • Cooperative broadcasting

    Publication Year: 1974, Page(s):317 - 324
    Cited by:  Papers (117)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (985 KB)

    This paper shows that several transmitters operating in an additive white Gaussian noise environment can send at rates strictly dominating time-multiplex and frequency-multiplex rates by use of a superposition scheme that pools the time, bandwidth, and power allocations of the transmitters. This pooling can be achieved without cooperative action, except for agreement on the actual rate of transmis... View full abstract»

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  • Trellis Encoding of memoryless discrete-time sources with a fidelity criterion

    Publication Year: 1974, Page(s):325 - 332
    Cited by:  Papers (71)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1092 KB)

    For memoryless discrete-time sources and bounded single-letter distortion measures, we derive a bound on the average per-letter distortion achievable by a trellis source code of fixed constraint length. For any fixed code rate greater than<tex>R(D^{\ast})</tex>, the rate-distortion function at<tex>D^{\ast}</tex>, this bound decreases toward<tex>D^{\ast}</tex>exp... View full abstract»

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  • Tree encoding of Gaussian sources

    Publication Year: 1974, Page(s):332 - 336
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (834 KB)

    Tree codes are known to be capable of performing arbitrarily close to the rate-distortion function for any memoryless source and single-letter fidelity criterion. Tree coding and tree search strategies are investigated for the discrete-time memoryless Gaussian source encoded for a signal-power-to-mean-squared-error ratio of about 30 dB (about 5 binary digits per source output). Also, a theoretical... View full abstract»

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  • Optimal coding with a single standard run length

    Publication Year: 1974, Page(s):336 - 343
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (957 KB)

    The optimum single standard run lengths for a binary first-order Markov source are derived and extended to multilevel first-order Markov sources. Maximization of the compression ratio is used as the criterion of optimality. When the output symbols are block coded, the optimal single standard run length<tex>n_i</tex>for each symbol is shown to satisfy an implicit equation of the form<... View full abstract»

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  • The optimum mean-square estimate for decoding binary block codes

    Publication Year: 1974, Page(s):344 - 351
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1089 KB)

    By the use of abstract Fourier analysis on groups, the optimum mean-square-error decoding rule is developed for a fixed block code. The optimum one-to-one coding role to be used with this optimum decoder is derived, and a procedure for simultaneous optimization over both encoding and decoding rules is given. It is shown that there is a linear encoding rule which is optimum. A system which implemen... View full abstract»

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  • Some long cyclic linear binary codes are not so bad

    Publication Year: 1974, Page(s):351 - 356
    Cited by:  Papers (38)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (983 KB)

    We show that when an inner linear cyclic binary code which has an irreducible check polynomial is concatenated with an appropriately chosen maximal-distance-separable outer code, then the overall code is cyclic Over<tex>GF(2)</tex>. Using this theorem, we construct a number of linear cyclic binary codes which are better than any previously known. In particular, by taking the inner code... View full abstract»

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  • Free distance bounds for convolutional codes

    Publication Year: 1974, Page(s):356 - 365
    Cited by:  Papers (48)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1559 KB)

    The best asymptotic bounds presently known on free distance for convolutional codes are presented from a unified point of view. Upper and lower bounds for both time-varying and fixed codes are obtained. A comparison is made between bounds for nonsystematic and systematic codes which shows that more free distance is available with nonsystematic codes. This result is important when selecting codes f... View full abstract»

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  • Four-phase Barker codes

    Publication Year: 1974, Page(s):366 - 371
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (895 KB)

    This paper considers four-phase Barker sequences. Several theorems are proved, and they are used to show that there are no new sequences with odd length<tex>\leq 31</tex>. Some similar theorems are proved for three-phase Barker sequences. View full abstract»

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  • Capacity-achieving input distributions for some amplitude-limited channels with additive noise (Corresp.)

    Publication Year: 1974, Page(s):372 - 374
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (497 KB)

    An additive noise channel wherein the noise is described by a piecewise constant probability density is shown to reduce to a discrete channel by means of an explicit construction. In addition, conditions are found which describe a class of continuous amplitude-limited channels for which the capacity-achieving input distribution is binary. View full abstract»

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  • Quantum Bayes estimation of the amplitude of a coherent signal (Corresp.)

    Publication Year: 1974, Page(s):374 - 376
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (439 KB)

    The complex amplitude of a coherent quantum signal in the presence of thermal noise is to be estimated when its real and imaginary parts have a Gaussian prior distribution. Cost functions of Gaussian, power-law, and delta-function forms are shown all to lead to the same optimum estimator. View full abstract»

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  • Error probabilities in random-phase binary optical signalling (Corresp.)

    Publication Year: 1974, Page(s):376 - 378
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (462 KB)

    Expressions for the error probabilities in the detection of binary coherent orthogonal equienergy optical signals of random phase in thermal background noise are derived. They converge to the classical expressions at high densities. Poisson models for background noise, however, lead to singular detection at high densities. View full abstract»

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  • Averaging logarithms for detection and estimation (Corresp.)

    Publication Year: 1974, Page(s):378 - 382
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    In a number of applications in signal processing it is desirable to estimate the logarithm of the average of noisy physical measurements by averaging<tex>M</tex>independent logarithms of the measurements. Only a modest number of bits are necessary in the logarithmic averaging process, which is used in logarithmic radar receivers to improve the effective dynamic range where post-detecti... View full abstract»

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  • Finite-memory algorithms for estimating the mean of a Gaussian distribution (Corresp.)

    Publication Year: 1974, Page(s):382 - 384
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (601 KB)

    Let<tex>\{X_n\}_{n=1}^{\infty}</tex>be independent random variables, each having a<tex>\mathcal{N}(\mu, \sigma^2)</tex>distribution. If we try to estimate<tex>\mu</tex>with an<tex>m</tex>-state learning algorithm, then the minimum mean-squared error is bounded below by that obtained by the best<tex>m</tex>-level quantizer (which requires ... View full abstract»

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  • Finite-memory classification of Bernoulli sequences using reference samples (Corresp.)

    Publication Year: 1974, Page(s):384 - 387
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (654 KB)

    It is shown that in two-way Bernoulli classification problems deterministic machines can perform as well as optimal randomized machines if their memory is increased by less than one bit. This is accomplished by allowing the algorithm to observe samples from both classes, thus in effect using the data source itself to provide the necessary randomization. An application to a simple communication pro... View full abstract»

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  • On tests with finite memory in finite time (Corresp.)

    Publication Year: 1974, Page(s):387 - 388
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (277 KB)

    The purpose of this correspondence is to display an inductive proof of an optimality result for testing symmetric simple hypotheses concerning a binomial parameter with a three-state memory and<tex>n</tex>observations. Specifically, it is shown that if one restricts attention to three-state automata allowing transitions only between adjacent states, then no artificial randomization is ... View full abstract»

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  • An adaptive-feedback coding scheme using incremental redundancy (Corresp.)

    Publication Year: 1974, Page(s):388 - 389
    Cited by:  Papers (164)  |  Patents (40)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (299 KB)

    A feedback decision scheme is proposed in which a punctured codeword is initially transmitted. If an uncorrectable error is detected, the receiver signals the transmitter to send another increment of redundancy. This procedure is continued if the aggregated word is still uncorrectable. View full abstract»

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  • A Tightened Upper Bound on the Error Probability of Binary Convolutional Codes with Viterbi Decoding

    Publication Year: 1974, Page(s):389 - 391
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (423 KB)

    Tighter upper bounds on the error event and the bit error probabilities, respectively, for maximum-likelihood decoding of binary convolutional codes on the binary symmetric channel are derived from upper bounds previously published by Viterbi [1]. The measured bit error rate<tex>P_b</tex>for a constraint length 3 decoder has been plotted versus the channel transition probability<tex... View full abstract»

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  • A decoding algorithm for binary block codes and<tex>J</tex>-ary output channels (Corresp.)

    Publication Year: 1974, Page(s):391 - 394
    Cited by:  Papers (60)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    A search algorithm is described to decode long binary block codes of any rate for the memoryless binary input<tex>J</tex>-ary output channel. It can be used directly to perform maximum-likelihood decoding or in a constrained version that gives considerably fewer searches at a small sacrifice in performance. Simulation results are given for a rate-l/2 code of length 128 and minimum Hamm... View full abstract»

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  • Conjectures on uniquely decipherable codes (Corresp.)

    Publication Year: 1974, Page(s):394 - 396
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    A conjecture concerning the codeword compositions of uniquely decipherable codes is proposed. This conjecture is shown to be equivalent to a related conjecture of Karp about the codeword costs of uniquely decipherable codes. A set of inequalities satisfied by ali prefix-condition codes is exhibited, and it is conjectured that these inequalities are valid for all uniquely decipherable codes. View full abstract»

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  • Lower bounds on the maximum cross correlation of signals (Corresp.)

    Publication Year: 1974, Page(s):397 - 399
    Cited by:  Papers (711)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (430 KB)

    Some communication systems require sets of signals with impulse-like autocorrelation functions and small cross correlation. There is considerable literature on signals with impulse-like autocorrelation functions hut little on sets of signals with small cross correlation. A possible reason is that designers put too severe a restriction on cross correlation magnitudes. This correspondence establishe... View full abstract»

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  • Review of 'Uncertain Dynamic Systems' (Schweppe, F. C.; 1973)

    Publication Year: 1974, Page(s):399 - 400
    Request permission for commercial reuse | PDF file iconPDF (563 KB)
    Freely Available from IEEE
  • Review of 'Pattern Recognition Techniques' (Ullman, J. R.; 1973)

    Publication Year: 1974, Page(s): 400
    Request permission for commercial reuse | PDF file iconPDF (181 KB)
    Freely Available from IEEE
  • Slant transform image coding (Ph.D. Thesis abstr.)

    Publication Year: 1974, Page(s): 401
    Request permission for commercial reuse | PDF file iconPDF (139 KB)
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IEEE Transactions on Information Theory publishes papers concerned with the transmission, processing, and utilization of information.

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Meet Our Editors

Editor-in-Chief
Alexander Barg

Department of Electrical and Computer Engineering and the Institute for Systems Research, University of Maryland

email: abarg-ittrans@ece.umd.edu