IEEE Transactions on Communications

Volume 26 Issue 2 • February 1978

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Displaying Results 1 - 21 of 21
  • [Front cover and table of contents]

    Publication Year: 1978, Page(s): 0
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    Freely Available from IEEE
  • Subjective Evaluation of an Adaptive Differential Voice Encoder with Oversampling and Entropy Coding

    Publication Year: 1978, Page(s):201 - 208
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (834 KB)

    An adaptive differential speech encoder was assessed using subjective evaluation procedures. The coder's adaptive quantizer was similar to the one used by Cohn and Melsa [1] and the predictor involved nonadaptive previous-sample feedback. The digital channel used to transmit the quantizer output levels was assumed error-free. Paired comparison tests were used to obtain scaled isopreference contour... View full abstract»

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  • Submarine Coaxial Cable Pressure Characteristics

    Publication Year: 1978, Page(s):246 - 253
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (566 KB)

    In equalization design of submarine coaxial cable system, the cable attenuation deviation due to pressure in deep sea bottom has significant weight. This paper treats the submarine coaxial cable characteristics pressure dependency. By using an artificial ocean test facility, 1.7 inch submarine coaxial cable attenuation, phase, capacitance and insulator core diameter were studied and their pressure... View full abstract»

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  • Receiver Structure for Saturating Channels

    Publication Year: 1978, Page(s):270 - 278
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (691 KB)

    A Maximum Likelihood receiver for binary phase-shift keyed signals is derived for the case when the channel includes a bandpass nonlinearity preceded and followed by sources of additive noise. This optimum receiver is then approximated for the case of a limitertype of channel and is seen to be a nonlinear function of both pre- and post-limiter signal to noise ratios and a normalized limiter softne... View full abstract»

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  • Multiaccess Model for Packet Switching with a Satellite Having Processing Capability: Delay Analysis

    Publication Year: 1978, Page(s):283 - 290
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (718 KB)

    The multiaccess model for satellite packet switching proposed by the authors [1] employs a frame format, with scheduling assignments broadcast from the satellite. The total delay recurred by a data packet in traversing the satellite channel consists of queueing delay, scheduling delay, transmission delay and propagation delay. In this paper we analyze the queueing and scheduling delays and compare... View full abstract»

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  • Comments on "A Per-Channel A/D Converter Having 15-Segment µ-255 Companding"

    Publication Year: 1978, Page(s): 305
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (106 KB)

    The above paper1 proposed an interpolative encoder for per-channel voiceband application. A description is given here of a very simple bidirectional shift register for use as a digital accumulator in such encoders. View full abstract»

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  • Comments on "A New Technique for Displaying Continuous Tone Images on a Bilevel Display"

    Publication Year: 1978, Page(s):309 - 310
    Cited by:  Papers (2)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (230 KB)

    It is shown that, when ordered dither is employed, the constrained-average algorithm presented in the above paper is equivalent to ordered-dither coding of a picture which has been subjected to a well-known method of edge enhancement. The magnitude of the parameterγ controls the degree of edge enhancement and the dither signal amplitude controls the picture contrast. View full abstract»

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  • [Back cover]

    Publication Year: 1978, Page(s): 0
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    Freely Available from IEEE
  • Bounds on Quantizer Performance in the Low Bit-Rate Region

    Publication Year: 1978, Page(s):300 - 304
    Cited by:  Papers (48)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    This paper investigates the optimum entropy versus distortion performance of quantizers optimized for uniform, Gaussian, Laplacian, and gamma-distributed memoryless sources which are useful models of the quantizer input signals in speech or picture coding schemes. We list the maximally obtainable signal-to-quantization noise ratios for one-dimensional optimum (i.e. entropy-coded) quantizers in the... View full abstract»

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  • Quantization Based on the Mean-Absolute-Error Criterion

    Publication Year: 1978, Page(s):267 - 270
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    Performance criteria for the design of optimum quantizers are considered. A distance criterion for quantizer input and output probability distribution functions is formulated, and its relationship to the usual distortion criteria is established. The criterion based on absolute error is shown to have unique properties, justifying its use as a performance index for optimum quantization. Numerical re... View full abstract»

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  • Receiver Design for Optical PPM Systems

    Publication Year: 1978, Page(s):295 - 300
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (560 KB)

    An optimum receiver structure for optical PPM systemics is considered and from this a simple sub-optimum receiver is proposed which offers significant SNR improvement relative to existing design approaches and yet requires few circuit changes. Receivers incorporating either p-i-n or avalanche photodiodes and FET or BJT preamplifiers are analyzed. The optimization technique relies on matching the f... View full abstract»

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  • The Effect of Non-Gaussian Noise on the Performance of Binary CPSK System

    Publication Year: 1978, Page(s):305 - 309
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    Upper and lower bounds on the probability of error of binary CPSK system subject to additive non-Gaussian noise and intersymbol interference are derived and the bounds are evaluated for square-wave signaling when the signal is pasSed through filters of Butterworth and Chebyshev transmission characteristics. It is assumed that the distribution of the non-Gaussian noise is characterized by skewness ... View full abstract»

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  • A Receiver with Memory for Fading Channels

    Publication Year: 1978, Page(s):278 - 283
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    In this paper, an adaptive receiver with memory for fading communication channels is considered. The receiver consists of an estimator and a detector. The estimator is a finite-memory MMSE estimator with decision-feedback which minimizes the probability of error of the receiver. Asymptotic approximations are employed to derive an adaptive decision role based on the estimate. An example is presente... View full abstract»

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  • The Rejection of Large CW Interferers in Spread Spectrum Systems

    Publication Year: 1978, Page(s):254 - 256
    Cited by:  Papers (24)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    An electronic CW interference rejection technique for spread spectrum systems is presented and analyzed. Analytical results indicate that essentially complete rejection is achieved. More conservative examination of performance indicates performance comparable to a notched filter implementation but with the greater flexibility of a narrowband tracking loop implementation. View full abstract»

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  • Delay Decomposition at a Single Server queue with Constant Service Time and Multiple Inputs

    Publication Year: 1978, Page(s):290 - 295
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    Two networks consisting of single server queues, each with a constant service time, are considered. The external inputs to each network are assumed to follow some general probability distribution. Several interesting equivaleneies that exist between the two networks considered are derived. This leads to the introduction of an important concept in delay decomposition. It is shown that the waiting t... View full abstract»

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  • Digital Whitening Techniques for Improving Spread Spectrum Communications Performance in the Presence of Narrowband Jamming and Interference

    Publication Year: 1978, Page(s):209 - 216
    Cited by:  Papers (96)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    Narrowband jamming and interference due to other users in spread spectrum communication systems can be effectively suppressed by using digital whitening. As a result, an impressive improvement in receiver performance can be obtained. The digital whitening is accomplished using a transversal filter whose coefficients are selected by either a Wiener algorithm or a maximum entropy algorithm. Filters ... View full abstract»

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  • Performance Evaluation for Transform Coding Using a Nonseparable Covariance Model

    Publication Year: 1978, Page(s):310 - 312
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    Intraframe transform coding of pictures for the case of a nonseparable covariance model is considered. Performances of the Walsh-Hadamard, discrete cosine and Karhunen-Loeve transforms are compared based on the compaction of signal energy in the transform components, and, the degree of decorrelation of the data. The results demonstrate that the performances of the discrete cosine and Karhunen-Lo&#... View full abstract»

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  • Volterra Systems with Random Inputs: A Formalized Approach

    Publication Year: 1978, Page(s):217 - 227
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (792 KB)

    The object of this work is to investigate the problem of Volterra systems driven by random inputs. General expressions for the second-order output statistics of a Volterra system are obtained and formalized. The input-output crosscorrelation and output autocorrelation functions are expressed in terms of higher order input autocorrelation functions. In the frequency domain, the cross-power and outp... View full abstract»

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  • Effects of Thermal Noise, Filtering and Co-Channel Interference on the Probability of Error in Binary Coherent PSK Systems

    Publication Year: 1978, Page(s):257 - 267
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    An analytical method for evaluating the bit error probability in Binary Coherent Phase Shift Keying (BCPSK) systems is presented. The system impairments considered are additive Gaussian noise, intersymbol interference and co-channel interference. The method is based on the power series expansion of the characteristic function of the interferences. Each characteristic function is expanded in a powe... View full abstract»

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  • Reliable Satellite Communications for a Specular Multipath Channel

    Publication Year: 1978, Page(s):235 - 246
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1152 KB)

    In many mobile satellite communication systems specular multipath exists and acts as a distortion to the transmitted message stream. In most cases there is a singular specular return which can be characterized by a delay and reflection coefficient. If this return is viewed as intersymbol interference on the channel, then it is possible to consider the resulting channel as modeled by a finite state... View full abstract»

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  • Nonlinear FM Distortion Equalizer

    Publication Year: 1978, Page(s):227 - 235
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (768 KB)

    A new approach to FM distortion equalization is suggested and a nonlinear equalizer operating in the baseband frequency range is presented. It is shown that, using analog multipliers and differentiators, a baseband equalizer can be designed which eliminates all types of distortion products. The synthesis of the FM distortion equalizer is given with minimum number of multipliers. Using the synthesi... View full abstract»

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Aims & Scope

IEEE Transactions on Communications focuses on all telecommunications including telephone, telegraphy, facsimile, and point-to-point television by electromagnetic propagation.

 

 

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Naofal Al-Dhahir
University of Texas at Dallas