IEEE Transactions on Communications

Issue 7 • July 1975

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  • [Front cover and table of contents]

    Publication Year: 1975, Page(s): 0
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    Freely Available from IEEE
  • The Design of Gradings with Small Interconnection Numbers for Random Hunt Selectors

    Publication Year: 1975, Page(s):714 - 721
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (798 KB)

    An earlier paper [2] presented algorithms for designing gradings for random hunt selectors, The gradings were designed to have a particular kind of combinatorial symmetry called "uniform overlap." The uniform overlap condition is a necessary but not a sufficient condition for grading design. The lack of sufficiency is particularly apparent for gradings With small interconnection numbers. The struc... View full abstract»

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  • Crosstalk Considerations for a 48 Channel PCM Repeatered Line

    Publication Year: 1975, Page(s):722 - 728
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (794 KB)

    Extension of the 24 channelT1carrier concept to a 48 channel system requires a careful investigation of the limitations imposed by the increased crosstalk noise susceptibility of 48 channel regenerators. Results of this paper demonstrate the feasibility of dual cable and single-screened cable operation of 48 channel lines at repeater spacings comparable toT1spacing. Operation... View full abstract»

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  • An Adaptive Electronic Circulator for Use in Telephones

    Publication Year: 1975, Page(s):728 - 731
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (351 KB)

    A design for an adaptive three-port electronic circulator is presented. The circuit has particular use in telephone work and this model can provide isolation when the terminating load varies over the range200 Omega - 1 kOmega. The whole circuit is realizable in microelectronic form. View full abstract»

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  • Performance of a Biphase Bandpass Communication System

    Publication Year: 1975, Page(s):757 - 761
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (503 KB)

    A binary bandpass communications system is considered, in which the ratio of bandwidth to intermediate frequency (IF) is not necessarily small. Closed-form expressions are given in the case when the receiver (IF) filter hasNdistinct poles. Explicit results, namely probabilities of error, are computed when the filter is a bandpass Butterworth filter. The effect ofk = f_{0}/f_{r} View full abstract»

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  • Short Constraint Length Rate 1/2 "Quick-Look" Codes

    Publication Year: 1975, Page(s):768 - 773
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (462 KB)

    Quick-look nonsystematic convolutional codes have the property that the information sequence may be recovered from the encoded sequence in straightforward fashion and with a minimum of error amplification. In this concise paper we investigate their relevant characteristics for constraint lengths less than eight and ratefrac{1}{2}and obtain a number of interesting and practically useful ... View full abstract»

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  • [Back cover]

    Publication Year: 1975, Page(s): 0
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    Freely Available from IEEE
  • Discrete-Time Synchronization of Communications Networks Having Variable Delays

    Publication Year: 1975, Page(s):782 - 785
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    A modification of a discrete-time method of synchronizing the clock frequencies in a digital communications network which makes the system frequency independent of time-varying transmission delays in the links of the network is discussed. View full abstract»

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  • Use of "Activity" Classes in Adaptive Transform Image Coding

    Publication Year: 1975, Page(s):785 - 786
    Cited by:  Papers (30)  |  Patents (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    The weighted sum of the absolute values of the transform coefficients, defined herein as the activity index, is proposed as an objective measure of scene busyness (i.e., the density of significant scene detail). For an image divided into subpictures, it is possible to classify each subpicture into a finite number (say four) of categories according to its computed activity index. A different coding... View full abstract»

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  • An Optimal Coding Scheme for a Certain Type of Ensemble

    Publication Year: 1975, Page(s):741 - 743
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    An optimal coding scheme is offered for binary messages with a limited number of successive runs of length 1 (i.e., strings of the form 010101..., in the messages, have a known limited length). A practical example is given of a case where such messages are found. View full abstract»

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  • The Economics and Performance of Satellite Packet Switching

    Publication Year: 1975, Page(s):732 - 741
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1104 KB)

    The economics and performance of packet-switched satellite systems operating in a broadcast mode are studied and compared to landline-based systems similar to the ARPANET. The fixed-packet length inefficiencies and the satellite channel utilization of the satellite systems are presented as functions of the message length distribution, the number of earth stations, the average message delay, and th... View full abstract»

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  • Signal-to-Intermodulation Noise in Biased Limiting Amplifiers

    Publication Year: 1975, Page(s):743 - 757
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (816 KB)

    This paper summarizes 1) harmonic signal output for a variety of class C power amplifier models and 2) other biased amplifier configurations when the input consists of an arbitrary number of carriers plus noise; it also demonstrates signal suppression and/ or enhancement in the class C amplification process for several signal sets and amplifier models, and it develops expressions for output signal... View full abstract»

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  • Performance Evaluation of Data Modems for the Aeronautical Satellite Channel

    Publication Year: 1975, Page(s):695 - 705
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1120 KB)

    Several modems and satellite subsystems were tested with the aid of an aeronautical channel simulation facility. The modems tested include a high-performance differential phase-shift keyed (DPSK) modem, a high-performance coherent phase-shift keyed (CPSK) modem, two hybrid voice-data modems, and a lower performance CPSK modem. Data performance results are presented in the form of probability of bi... View full abstract»

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  • Syndrome Decoding of Convolutional Codes

    Publication Year: 1975, Page(s):789 - 792
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    The classical Viterbi decoder recursively finds the trellis path (code word) closest to the received data. Given the received data, the syndrome decoder first forms a syndrome, instead. A recursive algorithm like Viterbi's is used to determine the noise sequence of minimum Hamming weight that can be a possible cause of this syndrome. Given the estimate of the noise sequence, one derives an estimat... View full abstract»

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  • A Characterization of Transionospheric Fading Communication Channel

    Publication Year: 1975, Page(s):773 - 776
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    Using a multiple-scatter propagation theory, the characteristics of the transionospheric satellite-earth communication links are related to the parameters of the ionosphere. General equations for the frequency correlation functions are derived. Some approximate solutions are obtained and numerical examples are given. Also discussed are the degree of coherence and potential applications of the proc... View full abstract»

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  • System Considerations for Short-Haul Multichannel Subscriber Carrier

    Publication Year: 1975, Page(s):776 - 781
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (512 KB)

    Solid-state technology is available to permit the design of multichannel station carrier systems with "prove-in" distances of 18 kft or less. Customer acceptance of these systems will depend on transmission performance, installation and maintenance ease, service reliability, and application restriction, as well as the per-channel installed cost. This paper discusses these parameters with regard to... View full abstract»

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  • Systematic Construction of Cyclically Permutable Code Words

    Publication Year: 1975, Page(s):786 - 789
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    A numerical procedure for determining the cyclically permutable code of any length over an arbitrary alphabet is outlined. This method is easily programmed on a digital computer. A formula for the Hamming weight distribution of the code is also given. The results for the 12 bit binary cyclically permutable code are presented along with the weight distribution of the binary codes through length 14. View full abstract»

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  • Performance of Hybrid Error Control Schemes of Satellite Channels

    Publication Year: 1975, Page(s):689 - 694
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    The effectiveness of hybrid error control schemes involving forward error correction (FEC) and automatic repeat request (ARQ) is examined for satellite channels. The principal features of the channel are: large round-trip transmission delay due to the satellite link, and burst errors introduced by the terrestrial links that connect the users to the satellite link. The performance is estimated for ... View full abstract»

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  • Analysis of Perception of Motion in Television Signals and its Application to Bandwidth Compression

    Publication Year: 1975, Page(s):761 - 768
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1064 KB)

    The method and results are reported of subjective assessment tests on the perception of motion in television signals. Discussed are applications of these results to the transmission technique for the difference between two adjacent frame signals. The main results are as follows. 1) Smoothness of motion is lost by field-repeating or frame-repeating TV signals, unless motion is slow. The just percep... View full abstract»

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  • A New Electronic Telephone Accounting System for Local Telephone Calls

    Publication Year: 1975, Page(s):705 - 714
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1024 KB)

    Telephone switching systems provide facilities to measure subscriber usage for billing purposes. As new telephone services are offered, additional equipment is often required to appropriately measure this usage. Rate plans are being considered by telephone companies to more appropriately reflect service rendered on local telephone calls and additional equipment is required. This paper describes an... 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