IEEE Transactions on Communications

Issue 5 • May 1978

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Displaying Results 1 - 25 of 38
  • [Front cover and table of contents]

    Publication Year: 1978, Page(s): 0
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  • Through the digital processor

    Publication Year: 1978, Page(s):489 - 492
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (551 KB)

    First Page of the Article
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  • LSI Processor for Digital Signal Processing and Its Application to 4800 Bit/s Modem

    Publication Year: 1978, Page(s):499 - 506
    Cited by:  Papers (8)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (946 KB)

    This paper describes a fast data processing LSI unit tailored to the digital signal processing (DSP) applications in the field of electrical communications. The results of successful application to the 4800 bit/s modem are also given. The LSI processor discussed here adopts a firmware control scheme to enhance the flexibility and freedom of application and extensively utilizes the pipeline process... View full abstract»

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  • Bit Rate Per Channel Halving in PCM Multiplexes by Speech Interpolation and Adaptive Quantization

    Publication Year: 1978, Page(s):638 - 646
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (850 KB)

    An all digital system, labeled PCM.RR. is presented, which enables the doubling of traffic capacity of PCM links. This is obtained, although keeping the transmission quality impairment very close to the normal PCM standards, by properly using "Adaptive Quantization" and "Speech Interpolation" performed by means of a "Speech Detector" that works directly on theA-law compressed digital si... View full abstract»

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  • Introduction to Papers on TDM/FDM Transmultiplexers

    Publication Year: 1978, Page(s):697 - 698
    Cited by:  Papers (10)
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    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1978, Page(s): 0
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  • A Microprocessor Controlled Digital Interface for Digital Satellite Systems

    Publication Year: 1978, Page(s):631 - 637
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    We describe exploratory work designed to demonstrate the feasibility of directly interfacing terrestrial digital carrier systems to digital satellite systems. Designed to accept up to 30 T1 carrier systems on the terrestrial side, the interface is designed as a common-control, bus-oriented time-division switch using a common time-slot interchanger for simultaneous switching of up- and down-links. ... View full abstract»

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  • A Low-Cost Real-Time Service Digital Signal Processor

    Publication Year: 1978, Page(s):626 - 631
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    The conceptual ideas and design features of a low cost digital signal processor intended for data acquisition/filtering and decision/control in telecommunications are discussed. The speed, lowcost and flexibility of the processor appear as a result of a mixed firmware/software architecture used in conjunction with a multi-level distribution of processing. The system is easily reprogrammable by rep... View full abstract»

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  • A High-Speed FFT Processor

    Publication Year: 1978, Page(s):690 - 696
    Cited by:  Papers (9)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    A high-speed, low-power, fast Fourier transform (FFT) processor is described in this paper. The FFT processor is designed around parallel arithmetic functions (16 by 16 multiplier and 16-bit adders) and can operate up to a 17.0-MHz clock rate. It performs a 128-point FFT in 250 μs at 16-MHz clock rate and therefore can be used for applications such as frequency-division multiplexing/timedivis... View full abstract»

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  • Passband Timing Recovery in an All-Digital Modem Receiver

    Publication Year: 1978, Page(s):517 - 523
    Cited by:  Papers (52)  |  Patents (28)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (624 KB)

    The performance of conventional modem receivers, where adaptive equalization is achieved by a digital transversal filter with tap gains spaced at the symbol interval, depends critically on the choice of the sampling phase. In this paper, a digital timing recovery loop is described and analyzed in the case of passband quadrature amplitude modulated data signals. Under conditions likely to be encoun... View full abstract»

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  • A Three-Dimensional Spatial Non-Linear Predictor for Television

    Publication Year: 1978, Page(s):578 - 583
    Cited by:  Papers (13)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (592 KB)

    This paper presents a three-dimensional non-linear prediction technique for use in differential pulse code modulation systems used to encode television signals. The prediction is a weighted sum of three estimates called representatives. Each representative is a nonlinear estimate based on previous pels in one of three planes containing the pel to be predicted. The paper contains an explanation of ... View full abstract»

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  • TDM-FDM Conversion Requiring Reduced Computation Complexity

    Publication Year: 1978, Page(s):707 - 719
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (976 KB)

    We present an approach to perform the conversion between two widely used multiplexing techniques in telephony, time division, multiplex (TDM) to frequency division multiplex (FDM), using digital signal processing techniques. By exploiting some results from the theory of computational complexity we reduce considerably the number of computations required. Furthermore the use of only nonrecursive (FI... View full abstract»

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  • Modulation Considerations for a 91 Mbit/s Digital Radio

    Publication Year: 1978, Page(s):523 - 528
    Cited by:  Papers (9)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (664 KB)

    The DRS-8 is a 91 Mbit/s long haul digital radio system designed for use in the Canadian 8 GHz frequency band. This paper discusses the considerations which lead to the choice of Quadrature Partial Response Signaling (QPRS) for this application. A method of implementing QPRS that circumvents power amplification difficulties and permits the use of simple conventional filtering and equalization is p... View full abstract»

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  • Digital Signal Processing with Program Synchronization Between Two Microprocessors

    Publication Year: 1978, Page(s):513 - 517
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    This paper addresses the synchronization problems which arise when real-time signal processing is performed in a multimicroprocessor machine. An experimental machine composed of two specialized microprocessors has been assembled: one to compute correlation and convolution products with a high thruput; the second one is a general purpose microprocessor which efficiently handles independent tasks on... View full abstract»

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  • Analysis of Digitally Generated Sinusoids with Application to A/D and D/A Converter Testing

    Publication Year: 1978, Page(s):669 - 675
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    Several aspects of the design of digital frequency synthesizers are considered, and a detailed analysis of the spectral purity of digitally synthesized frequencies is given. These results are then applied to a specific application: the testing of A/D and D/A converters. View full abstract»

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  • Tamed Frequency Modulation, A Novel Method to Achieve Spectrum Economy in Digital Transmission

    Publication Year: 1978, Page(s):534 - 542
    Cited by:  Papers (170)  |  Patents (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (912 KB)

    This paper describes a new type of frequency modulation, called Tamed Frequency Modulation (TFM), for digital transmission. The desired constraint of a constant envelope signal is combined with a maximum of spectrum economy which is of great importance, particularly in radio channels. The out-of-band radiation is substantially less as compared with other known constant envelope modulation techniqu... View full abstract»

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  • A Microprocessor-Based PSK Modem for Packet Transmission Over Satellite Channels

    Publication Year: 1978, Page(s):552 - 564
    Cited by:  Papers (17)  |  Patents (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1312 KB)

    This paper describes a microprocessor-based modem developed for use in a packet switching network over satellite channels. This digital modem can process both BPSK and QPSK packets with near optimum error rate performance over channels with marginal signal energy-to-noise density ratio. Of principal concern is the development of the discrete time algorithms which form the basis of the microinstruc... View full abstract»

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  • Simple Inductorless Automatic Line Equalizer for PCM Transmission Using New Variable Transfer Function

    Publication Year: 1978, Page(s):675 - 678
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    A new variable transfer function is proposed and its application to digital transmission is investigated. The realization of the new variable transfer function is developed for use in a digital transmission automatic line build out (ALBO) network. A simple inductorless ALBO network having ±15 dB variable range is demonstrated for use in 1.544 Mbit/s PCM transmission. Intersymbol interference ... View full abstract»

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  • An Experimental Microprocessor-Implemented 4800 Bit/s Limited Distance Voice Band PSK Modem

    Publication Year: 1978, Page(s):507 - 512
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    A low-cost 4800 bit/s modem is described which is applicable to limited distance, direct-copper channels. The modulation technique is eight-phase PSK and both the transmitter and receiver algorithms are aimed at economy of implementation in digital circuitry. The transmitter uses digitally stored waveform elements, and the detection and clock recovery techniques are based on received signal polari... View full abstract»

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  • Notchless Bi-Level Quantizer for Facsimile and Its Effect on Coding Efficiency

    Publication Year: 1978, Page(s):611 - 618
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (736 KB)

    With a facsimile bi-level quantizer, notches often occur along the white and black borders of a document when the output of a photosensor goes up and down around a threshold. The objects of this work are, first, to present a notchless bi-level quantizer, and secondly, to improve coding efficiency by using the quantizer. It is pointed out that quantization is comprised of many important aspects fro... View full abstract»

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  • Design Technique for Multiplexing Asynchronous Digital Video and Audio Signals

    Publication Year: 1978, Page(s):601 - 610
    Cited by:  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1088 KB)

    To apply digital transmission to the distribution of television program material it is necessary to encode both sound and picture signals, protect them from the effects of transmission errors and multiplex them into a form suitable for the transmission link that is to be used. Coding, error protection and multiplexing have all received extensive study but their combined application in a system has... View full abstract»

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  • Development of a TDM/FDM Transmultiplexer

    Publication Year: 1978, Page(s):726 - 733
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (672 KB)

    Recently, digital systems such as digital telephone switching systems and digital transmission paths are being introduced more and more into communications networks in which signals are handled with Time Division Multiplex (TDM). There still exists, on the other hand, a number of analog transmission paths in which signals are multiplexed with Frequency Division Multiplex (FDM). Therefore, it is im... View full abstract»

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  • An Improved Method for Digital SSB-FDM Modulation and Demodulation

    Publication Year: 1978, Page(s):720 - 725
    Cited by:  Papers (29)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    A new method for digital implementation of SSB-FDM modulation and demodulation is presented, which utilizes the FFT algorithm to reduce the multiplication rate. The hardware realization of the presented method is shown to be the simplest; it consists of only an FFT processor and a set of complex bandpass filters which operate at the same rate as the input baseband sequences; no signal conversions ... View full abstract»

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  • A Bandwidth Compressive Modulation System Using Multi-Amplitude Minimum Shift Keying (MAMSK)

    Publication Year: 1978, Page(s):543 - 551
    Cited by:  Papers (25)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1096 KB)

    A bandwidth compressive modem making use of multiamplitude minimum shift keying (MAMSK) has been designed and implemented in a laboratory environment at microwave frequencies. This system achieves a substantial bandwidth reduction over binary PSK and operates within 0.5 dB of theoretical performance. A number of easily implemented microwave transmitters have been designed to generate the required ... View full abstract»

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  • Carrier and Clock Recovery for 8 PSK Synchronous Demodulation

    Publication Year: 1978, Page(s):528 - 533
    Cited by:  Papers (6)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (648 KB)

    Synchronous demodulation of Phase-shift-keyed transmissions requires the recovery of carrier and clock timing signals. Envelope detection of the 70 MHz IF signal is used to recover clock, and baseband processing is used to recover carrier for an 8 PSK digital radio with a data rate of 90 Mbits/s in the 11 GHz band. A sequential phase detector is used in a high noise application. Two versions of th... 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