IEEE Transactions on Information Theory

Volume 36 Issue 4 • July 1990

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Displaying Results 1 - 25 of 34
  • epsilon -entropy and critical distortion of random fields

    Publication Year: 1990, Page(s):717 - 725
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (633 KB)

    The link between epsilon -entropy for binary random fields and the Lee-Yang theorem in statistical mechanics makes it possible to prove the existence of positive critical distortion for most binary random fields with pair interactions and some with many body interactions. Lower bounds for critical distortion of random fields on two-dimensional (2-D) lattices have been obtained. In particular, the ... View full abstract»

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  • Nonequiprobable signaling on the Gaussian channel

    Publication Year: 1990, Page(s):726 - 740
    Cited by:  Papers (116)  |  Patents (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1277 KB)

    Signaling schemes for the Gaussian channel based on finite-dimensional lattices are considered. The signal constellation consists of all lattice points within a region R, and the shape of this region determines the average signal power. Spherical signal constellations minimize average signal power, and in the limit as N to infinity , the shape gain of the N-sphere over the N-cube approaches pi e/6... View full abstract»

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  • Vector coding for partial response channels

    Publication Year: 1990, Page(s):741 - 762
    Cited by:  Papers (135)  |  Patents (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1873 KB)

    A linear technique for combining equalization and coset codes on partial response channels with additive white Gaussian noise is developed. The technique, vector coding, uses a set of transmit filters or 'vectors' to partition the channel into an independent set of parallel intersymbol interference (ISI)-free channels for any given finite (or infinite) block length. The optimal transmit vectors fo... View full abstract»

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  • The method of poles: a coding method for constrained channels

    Publication Year: 1990, Page(s):763 - 772
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (876 KB)

    A method for solving coding problems involving channels restricted by finite state constraints is presented. The method was introduced by P.A. Franaszek (1969) and is based on the computation of a set of principal states. It is proved that state-independent decoding is guaranteed. The main result is that the transducer constructed using the method is a local automaton in its output. The method is ... View full abstract»

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  • Focused codes for channels with skewed errors

    Publication Year: 1990, Page(s):773 - 783
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (927 KB)

    Consider a channel with inputs and outputs in the field F/sub q/(q>2). It is said that the channel is skewed on a set B contained in/implied by F/sub q/* if the additive noise generated by the channel is likely to lie in B, i.e. B is a set of common errors. The concern is the construction of focused codes that are appropriate for such channels. It is said that a code is (t/sub 1/,t/sub 2/)-focu... View full abstract»

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  • Sigma-delta modulation with i.i.d. Gaussian inputs

    Publication Year: 1990, Page(s):784 - 798
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1108 KB)

    The response of a single-loop sigma-delta modulator to an independent identically distributed (i.i.d.) Gaussian input signal is analyzed. A continuous-time stochastic model is developed and the connection of the model to the system is described. A condition is given so that the difference between the behavior of the model and that of the true system can be made arbitrarily small. Theories from ren... View full abstract»

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  • A study of vector quantization for noisy channels

    Publication Year: 1990, Page(s):799 - 809
    Cited by:  Papers (343)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1049 KB)

    Several issues related to vector quantization for noisy channels are discussed. An algorithm based on simulated annealing is developed for assigning binary codewords to the vector quantizer code-vectors. It is shown that this algorithm could result in dramatic performance improvements as compared to randomly selected codewords. A modification of the simulated annealing algorithm for binary codewor... View full abstract»

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  • An asymptotically optimal random modem and detector for robust communication

    Publication Year: 1990, Page(s):810 - 821
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1041 KB)

    Coherent communication over a waveform channel corrupted by thermal noise and by an unknown and arbitrary interfering signal of bounded power is considered. For a fixed encoder, a random modulator/demodulator (modem) and detector are derived. They asymptotically minimize the worst-case error probability as the blocklength of the encoder becomes large. This optimal modem is independent of the encod... View full abstract»

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  • On the quadratic spans of DeBruijn sequences

    Publication Year: 1990, Page(s):822 - 829
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (718 KB)

    The quadratic span of a periodic binary sequence is defined to be the length of the shortest quadratic feedback shift register (FSR) that generates it. An algorithm for computing the quadratic span of a binary sequence is described. The required increase in quadratic span is determined for the special case of when a discrepancy occurs in a linear FSR that generates an initial portion of a sequence... View full abstract»

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  • Cross spectral analysis of nonstationary processes

    Publication Year: 1990, Page(s):830 - 835
    Cited by:  Papers (64)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (550 KB)

    Consideration is given to the generalization of stationary cross spectral analysis methods to a class of nonstationary processes, specifically, the class of semistationary finite energy processes possessing sample functions that are of finite energy almost surely. A new quantity called the time-frequency coherence (TFC) is defined, and it is demonstrated that its properties are analogous to those ... View full abstract»

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  • Time-reversion of a hybrid state stochastic difference system with a jump-linear smoothing application

    Publication Year: 1990, Page(s):836 - 847
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1093 KB)

    The reversion in time of a stochastic difference equation in a hybrid space with a Markovian solution is presented. The reversion is obtained by a martingale approach, which previously led to reverse time forms for stochastic equations with Gauss-Markov or diffusion solutions. The reverse time equations follow from a particular noncanonical martingale decomposition, while the reverse time equation... View full abstract»

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  • The structure and design of realizable decision feedback equalizers for IIR channels with colored noise

    Publication Year: 1990, Page(s):848 - 858
    Cited by:  Papers (24)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1055 KB)

    A simple algorithm for optimizing decision feedback equalizers (DFEs) by minimizing the mean-square error (MSE) is presented. A complex baseband channel and correct past decisions are assumed. The dispersive channel may have infinite impulse response, and the noise may be colored. Consideration is given to optimal realizable (stable and finite-lag smoothing) forward and feedback filters in discret... View full abstract»

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  • A Karhunen-Loeve-like expansion for 1/f processes via wavelets

    Publication Year: 1990, Page(s):859 - 861
    Cited by:  Papers (179)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (271 KB)

    While so-called 1/f or scaling processes emerge regularly in modeling a wide range of natural phenomena, as yet no entirely satisfactory framework has been described for the analysis of such processes. Orthonormal wavelet bases are used to provide a new construction for nearly 1/f processes from a set of uncorrelated random variables.<<ETX>> View full abstract»

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  • Variable-to-fixed length codes are better than fixed-to-variable length codes for Markov sources

    Publication Year: 1990, Page(s):861 - 863
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (229 KB)

    It is demonstrated that for finite-alphabet, kth-order ergodic Markov sources (i.e. memory of k letters), a variable-to-fixed length code is better than the best fixed-to-variable length code (Huffman code). It is shown how to construct a variable-to-fixed length code for a kth order ergodic Markov source, which compresses more effectively than the best fixed-to-variable code.<<ETX>> View full abstract»

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  • A limit theorem for n-phase Barker sequences

    Publication Year: 1990, Page(s):863 - 868
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (329 KB)

    It is proved that for 3<or=L<or=19, except for L=6, the total number of normalized n-phase Barker sequences of length L increases without limit as n goes to infinity.<<ETX>> View full abstract»

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  • Optical orthogonal codes-new bounds and an optimal construction

    Publication Year: 1990, Page(s):866 - 873
    Cited by:  Papers (156)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (598 KB)

    A technique for constructing optimal OOCs (optical orthogonal codes) is presented. It provides the only known family of optimal (with respect to family size) OOCs having lambda =2. The parameters (n, omega , lambda ) are respectively (p/sup 2m/-1, p/sup m/+1,2), where p is any prime and the family size is p/sup m/-2. Three distinct upper bounds on the size of an OOC are presented that, for many va... View full abstract»

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  • A new construction of two-dimensional arrays with the window property

    Publication Year: 1990, Page(s):873 - 876
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (463 KB)

    It is shown how row-complete Latin squares and Tuscan squares can be used to construct nonbinary 1-D and 2-D arrays that have the u*v horizontal and/or vertical window property for all sufficiently large windows. It is shown how binary arrays with a similar property can be derived. Since an array can only be a perfect map for one particular size of window, the arrays that are constructed are not p... View full abstract»

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  • Algebraic decoding of the (32, 16, 8) quadratic residue code

    Publication Year: 1990, Page(s):876 - 880
    Cited by:  Papers (49)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (490 KB)

    An algebraic decoding algorithm for the 1/2-rate (32, 16, 8) quadratic residue (QR) code is found. The key idea of this algorithm is to find the error locator polynomial by a systematic use of the Newton identities associated with the code syndromes. The techniques developed extend the algebraic decoding algorithm found recently for the (32, 16, 8) QR code. It is expected that the algebraic approa... View full abstract»

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  • Pseudocyclic maximum-distance-separable codes

    Publication Year: 1990, Page(s):880 - 884
    Cited by:  Papers (49)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (534 KB)

    The (n, k) pseudocyclic maximum-distance-separable (MDS) codes modulo (x/sup n/-a) over GF(q) are considered. Suppose that n is a divisor of q+1. If n is odd, pseudocyclic MDS codes exist for all k. However, if n is even, nontrivial pseudocyclic MDS codes exist for odd k (but not for even k) if a is a quadratic residue in GF(q), and they exist for even k (but not for odd k) if a is not a quadratic... View full abstract»

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  • Decoder malfunction in BCH decoders

    Publication Year: 1990, Page(s):884 - 889
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (658 KB)

    A t-error-correcting bounded-distance decoder either produces the codeword nearest the received vector (if there is a codeword at distance no more than t) or indicates that no such codeword exists. However, BCH decoders based on the Peterson-Gorenstein-Zierler algorithm or the Euclidean algorithm can malfunction and produce output vectors that are not codewords at all. For any integer i no greater... View full abstract»

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  • On decoding unequal error protection product codes

    Publication Year: 1990, Page(s):890 - 895
    Cited by:  Papers (2)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (505 KB)

    The decoding of unequal error protection product codes, which are a combination of linear unequal error protection (UEP) codes and product codes, is addressed. A nonconstructive proof of the existence of a good error-erasure-decoding algorithm is presented; however, obtaining the decoding procedure is still an open research problem. A particular subclass of UEP product codes is considered, includi... View full abstract»

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  • New lower bounds for covering codes

    Publication Year: 1990, Page(s):895 - 899
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (354 KB)

    Some new lower bounds on mod C mod for a binary linear (n, k)R code C with n+1=t(R+1)-r(0<or=r<R+1, t>2 odd) or with n+1=t(R+1)-1(t>2 even) are obtained. These bounds improve the sphere covering bound considerably and give several new values and lower bounds for the function t(n, k), the smallest covering radius of any (n, k) code.<<ETX>> View full abstract»

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  • Constructions of error-correcting DC-free block codes

    Publication Year: 1990, Page(s):899 - 905
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (757 KB)

    Two DC-free codes are presented with distance 2d, b>or=1 length 2n+2r(d-1) for d<or=3 and length 2n+2r(d-1)(2d-1) for d>3, where r is the least integer >or=log/sub 2/ (2n+1). For the first code l=4, c=2, and the asymptotic rate of this code is 0.7925. For the second code l=6, c=3, and the asymptotic rate of this code is 0.8858. Asymptotically, these rates achieve the channel capacity. ... View full abstract»

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  • Decoding the Golay code with Venn diagrams

    Publication Year: 1990, Page(s):906 - 910
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (468 KB)

    A decoding algorithm, based on Venn diagrams, for decoding the (23, 12, 7) Golay code is presented. The decoding algorithm is based on the design properties of the parity sets of the code. As for other decoding algorithms for the Golay code, decoding can be easily done by hand.<<ETX>> View full abstract»

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  • A general decoding technique applicable to replicated file disagreement location and concatenated code decoding

    Publication Year: 1990, Page(s):911 - 917
    Cited by:  Papers (40)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (685 KB)

    Code symbols are treated as vectors in an r-dimensional vector space F/sup r/ over a field F. Given any (n, k) linear block code over F with minimum distance d, it is possible to derive an (n, k) code with symbols over F/sup r/, also with minimum distance d, which can correct any pattern of d-2 or fewer symbol errors for which the symbol errors as vectors are linearly independent. This is about tw... View full abstract»

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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