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IEEE Transactions on Communication Technology

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  • Data Transmission by Frequency-Division Multiplexing Using the Discrete Fourier Transform

    Publication Year: 1971, Page(s):628 - 634
    Cited by:  Papers (1127)  |  Patents (173)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (621 KB)

    The Fourier transform data communication system is a realization of frequency-division multiplexing (FDM) in which discrete Fourier transforms are computed as part of the modulation and demodulation processes. In addition to eliminating the bunks of subcarrier oscillators and coherent demodulators usually required in FDM systems, a completely digital implementation can be built around a special-pu... View full abstract»

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  • The Raisting Satellite Earth Station and Its System Noise Temperature

    Publication Year: 1967, Page(s):848 - 854
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    Features of the German satellite earth station at Raisting are cited in this paper. One essential criterion, the noise performance, is discussed in particular. The 25-meter Cassegrain antenna with horn reflector feed (covered by a radome) has been subjected to extended measurements of the system noise temperature. The results show the relation between the system noise temperature and the antenna e... View full abstract»

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  • The Divergence and Bhattacharyya Distance Measures in Signal Selection

    Publication Year: 1967, Page(s):52 - 60
    Cited by:  Papers (751)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (932 KB)

    Minimization of the error probability to determine optimum signals is often difficult to carry out. Consequently, several suboptimum performance measures that are easier than the error probability to evaluate and manipulate have been studied. In this partly tutorial paper, we compare the properties of an often used measure, the divergence, with a new measure that we have called the Bhattacharyya d... View full abstract»

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  • Convolutional Codes and Their Performance in Communication Systems

    Publication Year: 1971, Page(s):751 - 772
    Cited by:  Papers (547)  |  Patents (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2234 KB)

    This tutorial paper begins with an elementary presentation of the fundamental properties and structure of convolutional codes and proceeds with the development of the maximum likelihood decoder. The powerful tool of generating function analysis is demonstrated to yield for arbitrary codes both the distance properties and upper bounds on the bit error probability for communication over any memoryle... View full abstract»

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  • Performance of an Efficient Parallel Data Transmission System

    Publication Year: 1967, Page(s):805 - 811
    Cited by:  Papers (374)  |  Patents (58)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (658 KB)

    A parallel quadrature AM data transmission system may be implemented with a number of overlapping channels, each carrying a signaling rateb, spacedb/2apart in frequency. When a large number of channels are used, the system allows transmission speeds very close to the Nyquist rate, with little sensitivity to delay and amplitude distortion of the transmission medium. The receiv... View full abstract»

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  • Dither Signals and Their Effect on Quantization Noise

    Publication Year: 1964, Page(s):162 - 165
    Cited by:  Papers (207)  |  Patents (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (354 KB)

    In this paper, the conditions a dither signal must meet so that the quantizer noise can be considered independent of the signal are derived for a quantizer having a finite number of levels. An infinite class of dither signals which satisfy these conditions is given. It is seen that the most useful member of this class is one whose probability density function is uniformly distributed over a quanti... View full abstract»

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  • An Adaptive Decision Feedback Equalizer

    Publication Year: 1971, Page(s):281 - 293
    Cited by:  Papers (82)  |  Patents (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1272 KB)

    An adaptive decision feedback equalizer to detect digital information transmitted by pulse-amplitude modulation (PAM) through a noisy dispersive linear channel is described, and its performance through several channels is evaluated by means of analysis, computer simulation, and hardware simulation. For the channels considered, the performance of both the fixed and the adaptive decision feedback eq... View full abstract»

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  • Demodulation of Single-Sideband Signals Via Envelope Detection

    Publication Year: 1966, Page(s):22 - 30
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (920 KB)

    Present day single-sideband (SSB) technology is based on synchronous demodulation, with implicit stringent stability requirements. This factor has deterred the use of SSB in some services in which it might be advantageous. There are two general ways to mitigate the stability problem: by transmitting a pilot carrier to synchronize a local oscillator, and by extracting the information signal from th... View full abstract»

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  • Viterbi Decoding for Satellite and Space Communication

    Publication Year: 1971, Page(s):835 - 848
    Cited by:  Papers (245)  |  Patents (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1291 KB)

    Convolutional coding and Viterbi decoding, along with binary phase-shift keyed modulation, is presented as an efficient system for reliable communication on power limited satellite and space channels. Performance results, obtained theoretically and through computer simulation, are given for optimum short constraint length codes for a range of code constraint lengths and code rates. System efficien... View full abstract»

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  • M-ary Poisson Detection and Optical Communications

    Publication Year: 1969, Page(s):208 - 216
    Cited by:  Papers (50)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (902 KB)

    This paper presents an investigation of the problem of maximum likelihood detection of one ofMPoisson processes in a background of additive Poisson noise. When the observables correspond to counts of emitted photoelectrons, the problem models a discrete version of a coherentM-ary optical communication system using photon counters in the presence of background radiation. Consi... View full abstract»

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  • The Kalman Filter for the Equalization of a Digital Communications Channel

    Publication Year: 1971, Page(s):1137 - 1141
    Cited by:  Papers (77)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    Consideration is given to the use of the discrete Kalman filter as an equalizer for digital binary transmission in the presence of noise and intersymbol interference. When the channel is modeled as ann-tap transversal filter, the Kalman filter assumes a similar form with "feed forward and feedback." It is shown how the Kalman filter can be used to estimate both the tap weights and the b... View full abstract»

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  • Burst-Correcting Codes for the Classic Bursty Channel

    Publication Year: 1971, Page(s):772 - 781
    Cited by:  Papers (114)  |  Patents (35)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1222 KB)

    The purpose of this paper is to organize and clarify the work of the past decade on burst-correcting codes. Our method is, first, to define an idealized model, called the classic bursty channel, toward which most burst-correcting schemes are explicitly or implicitly aimed; next, to bound the best possible performance on this channel; and, finally, to exhibit classes of schemes which are asymptotic... View full abstract»

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  • Experimental Confirmation of an HF Channel Model

    Publication Year: 1970, Page(s):792 - 803
    Cited by:  Papers (134)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1230 KB)

    Specially designed HF ionospheric propagation measurements were made and analyzed to confirm the validity and bandwidth limitations of a proposed stationary HF ionospheric channel model. In the model, the input (transmitted) signal feeds an ideal delay line and is delivered at several taps with adjustable delays, one for each resolvable ionospheric modal component. Each delayed signal is modulated... View full abstract»

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  • A Theoretical Study of Performance of an Orthogonal Multiplexing Data Transmission Scheme

    Publication Year: 1968, Page(s):529 - 540
    Cited by:  Papers (147)  |  Patents (35)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (997 KB)

    This paper presents a theoretical analysis of the performance of an orthogonal multiplexing data transmission scheme (parallel transmission scheme) subject to a number of degrading factors normally encountered by a practical operating system. The factors considered jointly are sampling time error, carrier phase offset, and nonideal phase characteristics of transmitting and receiving filters. Perfo... View full abstract»

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  • Probabilities of Error for Adaptive Reception of M-Phase Signals

    Publication Year: 1968, Page(s):71 - 81
    Cited by:  Papers (115)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1010 KB)

    Probabilities of error are derived for 2- and 4-phase signaling over anL-diversity branch, time-invariant, additive Gaussian noise channel and forM-phase signaling over anLdiversity branch, Rayleigh fading, additive Gaussian noise channel. Both channels corrupt the signaling waveforms transmitted through them by introducing an additive Gaussian noise and an unknown... View full abstract»

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  • Carrier Transmission of Binary Data in a Restricted Band

    Publication Year: 1970, Page(s):295 - 304
    Cited by:  Papers (89)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (948 KB)

    The spectra of digital frequency modulation (FM) signals have been observed to be narrow compared with the spectra of digital baseband signals or the corresponding amplitude modulation (AM) and phase modulation (PM) signals. This suggests a high efficiency of transmission in terms of occupied bandwidth for binary FM. Here the desirability of digital FM systems is investigated further with an exami... View full abstract»

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  • Correlative Digital Communication Techniques

    Publication Year: 1964, Page(s):128 - 135
    Cited by:  Papers (77)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (807 KB)

    A new method for the transmission of intelligence by means of a signal having certain correlation properties has been evolved. The theoretical and practical aspects of this concept are presented. An important advantage of these techniques is that for a fixed performance criteria, considerably higher speeds are possible compared to the presently known methods. In addition, the implementation is sim... View full abstract»

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  • Cycle Slipping in a First-Order Phase-Locked Loop

    Publication Year: 1968, Page(s):255 - 260
    Cited by:  Papers (32)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (582 KB)

    In this paper a model for a carrier plus narrowband noise is presented, and with its aid the expected number of cycle slipping events per second for a first-order phase-locked loop (PLL) driven by a narrowband noise corrupted carrier, both with and without a limiter, is determined. Experimental data are presented which indicate the extreme accuracy of the results obtained with the use of this mode... View full abstract»

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  • The Design of a Pulse-Position Modulated Optical Communication System

    Publication Year: 1969, Page(s):670 - 676
    Cited by:  Papers (34)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (744 KB)

    In recent literature the advantages of an idealized narrow-width pulse-position modulated (PPM) optical communication system, using coherent sources and direct photodetection, have been shown. In this paper the practical design of such an operating PPM link is considered. System performance in terms of error probabilities and information rates is derived in terms of key parameters, such as power l... View full abstract»

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  • Space DIversity on Line-of-Sight Microwave Systems

    Publication Year: 1968, Page(s):119 - 133
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2611 KB)

    Deep fading on line-of-sight microwave paths is usually a result of multipath interference phenomena. Frequency diversity has been the most common method of protecting against such fading. In the past few years, vertical space diversity has also come into use. This paper discusses its characteristics, methods of determining spacings, and describes some results achieved. It is concluded that vertic... View full abstract»

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  • Generalization of a Techinque for Binary Data Communication

    Publication Year: 1966, Page(s):67 - 68
    Cited by:  Papers (140)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (230 KB)

    A technique for binary data transmission is described, in which each binary symbol is chosen to be a prescribed superposition ofnimpulses of form(sin 2piFt)/2piFt, spaced at intervals 1/2F. Such superposition leads to more than two received levels with binary input, but in return permits realization of the Nyquist rate (2F symbols/s in bandwidthF). Appropriate choi... View full abstract»

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  • The Effect of Gaussian Error in Maximal Ratio Combiners

    Publication Year: 1971, Page(s):492 - 500
    Cited by:  Papers (154)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (658 KB)

    In a fading channel, maximal ratio diversity combilling improves the average signal-to-noise ratio over thatof a single branch in proportion to the number of diversity branches combined. However, its main advantage is the reduction of the probability of deep fades. The effect of Gaussian errors in the combiner weighting factors on the probability distribution of the output signal-to-noise ratio is... View full abstract»

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  • Nonlinear Phase Shift in Traveling-Wave Tubes as Applied to Multiple Access Communications Satellites

    Publication Year: 1970, Page(s):37 - 48
    Cited by:  Papers (47)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1709 KB)

    A modern communications satellite typically amplifies many frequency-modulated radio-frequency carriers in a single common amplifier. The nonlinear phase versus input power behavior of traveling-wave tubes (TWT) and its impact on intermodulation noise and intelligible crosstalk is treated. A theoretical model is presented, which allows calculation of the multicarrier performance of the TWT, and an... View full abstract»

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  • Design and Characteristics of Coaxial Cables for Community Antenna Television

    Publication Year: 1966, Page(s):334 - 340
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (741 KB)

    Outlined in this paper are some of the more important requirements imposed on coaxial cable designed for community antenna television, popularly termed CATV. Examples of techniques for deriving best economic designs are discussed, and an example illustrating one such analysis is presented. Several designs, intended to meet such requirements, are reviewed. View full abstract»

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  • The Performance of FSK Permutation Modulations in Fading Channels and Their Comparison Based on a General Method for the Comparison of M-ary Modulations

    Publication Year: 1969, Page(s):616 - 640
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2656 KB)

    A problem that arises in multipath fading channels is that of finding a modulation which enables one to obtain high data rates and at the same time does not lead to an excessively complicated system implementation or the requirement of excessive transmitter power. In many dispersive channels the product of time dispersion and Doppler spread is large, so that coherent modulation systems are not fea... View full abstract»

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  • A Variable-Step-Size Robust Delta Modulator

    Publication Year: 1971, Page(s):1033 - 1044
    Cited by:  Papers (37)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1576 KB)

    An optimum adaptive delta modulator-demodulator configuration is derived. This device utilizes two past samples to obtain a step size which minimizes the mean square error for a Markov Gaussian source. The optimum system is compared using computer simulations with the linear delta modulator and an enhanced Abate delta modulator. In addition the performance is compared to the rate distortion bound ... View full abstract»

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  • Phase-Ambiguity Resolution in a Four-Phase PSK Communications System

    Publication Year: 1971, Page(s):1200 - 1210
    Cited by:  Papers (12)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1004 KB)

    The constraints of digital satellite communications systems have led to the derivation of a method for resolving the problem of recovered-carrier phase ambiguity in a coherent fourphase phase-shift-keying (PSK) communications system while simultaneously providing synchronization information. This method is described for the general case and a general implementation is given. In addition, implement... View full abstract»

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  • Adaptive Feedback Communications

    Publication Year: 1968, Page(s):29 - 34
    Cited by:  Papers (163)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (590 KB)

    A scheme for transmitting binary signals through a Rayleigh fading multipath medium is analyzed. The scheme envisions an adaptive receiver and a feedback channel. The feedback channel conveys information to the transmitter on the forward channel state learned at the receiver. The transmitter uses this information to modify transmission. Results that show the improvement in performance of the syste... View full abstract»

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  • Matched Filters for Rectangular, Raised Cosine, and Half Sine Wave Signals

    Publication Year: 1971, Page(s):369 - 371
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    Practical constructions of matched filters for the typical waveshape of pulsed signals are shown. Each filter consists of a prefilter, delay line, and attenuator. The degraduation of output signal-to-noise ratio (SNR) due to loss factor in each prefilter is calculated. View full abstract»

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  • Decision-Directed Digital Adaptive Equalization Technique for High-Speed Data Transmission

    Publication Year: 1970, Page(s):625 - 632
    Cited by:  Papers (117)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (721 KB)

    The digital adaptive equalization technique presented is characterized by a relatively simple algorithm and unique design features that permit fast adaptation in the decision-directed mode. For example, at 4800 bit/s the initial error rate in this mode may be as high as 25 percent, yet adaptation is assured. The equalization process is applied to the modified duobinary technique, but the principle... View full abstract»

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  • Simultaneous Adaptive Estimation and Decision Algorithm for Carrier Modulated Data Transmission Systems

    Publication Year: 1971, Page(s):268 - 280
    Cited by:  Papers (105)  |  Patents (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1140 KB)

    The problems of sequence decision, sample timing, and carrier phase recovery in a class of linear modulation data transmission systems are treated from the viewpoint of multiparameter estimation theory. The structure of the maximumlikelihood estimator is first obtained, and a decision-directed receiver is then derived. These receivers are different from the conventional one in that the carrier pha... View full abstract»

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  • Transmission of Multiplexed PAM Signals Over Multiple Channel and Diversity Systems

    Publication Year: 1970, Page(s):520 - 526
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (679 KB)

    It is well known that the optimum receiver for pulse-amplitude-modulated (PAM) signals, transmitted over a single channel, consists of a cascade of continuous and transversal filters. It is shown that an extended structure of this type is also optimum for the completely general case ofMmultiplexed PAM signals transmitted over random-time and frequency-dispersive multichannel systems wit... View full abstract»

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  • Image Coding by Linear Transformation and Block Quantization

    Publication Year: 1971, Page(s):50 - 62
    Cited by:  Papers (105)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1837 KB)

    The feasibility of coding two-dimensional data arrays by first performing a two-dimensional linear transformation on the data and then block quantizing the transformed data is investigated. The Fourier, Hadamard, and Karhunen-Loève transformations are considered. Theoretical results for Markov data and experimental results for four pictures comparing these transform methods to the standard me... View full abstract»

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  • An Analysis of the Capabilities of Polybinary Data Transmission

    Publication Year: 1965, Page(s):312 - 319
    Cited by:  Papers (10)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (783 KB)

    The capabilities of the polybinary technique for transmission of digital data in absolutely band-limited channels are evaluated by analysis and experiment. Relative bit rates and probabilities of error per bit are used to compare the various polybinary systems with each other and with the more conventional multilevel techniques of data transmission. It is concluded that duobinary transmission can ... View full abstract»

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  • Subsurface Electromagnetic Telecommunication - A Review

    Publication Year: 1971, Page(s):1217 - 1228
    Cited by:  Papers (26)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1127 KB)

    We present a review of the telecommunication possibilities for terminals that are buried in the earth or submerged in the sea. The important role of the operating frequency is stressed. Without being comprehensive, we discuss the relevance of the large number of theoretical papers on electromagnetic waves in conducting media. Our most important recommendation is that the highfrequency band be give... View full abstract»

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  • Further Results on Nyquist's Problem in Pulse Transmission

    Publication Year: 1968, Page(s):337 - 340
    Cited by:  Papers (75)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (303 KB)

    The Nyquist criterion specifies pulse shapes for a synchronous pulse amplitude modulation (PAM) signal which produce no intersymbol interference when the signal is sampled at the proper instants. For bandwidths in excess of one half the pulse repetition rate, the criterion is not uniquely satisfied. This paper considers the selection of pulse shapes for a single-sideband carrier signal which, in a... View full abstract»

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  • A Troposcatter Channel Model

    Publication Year: 1969, Page(s):130 - 137
    Cited by:  Papers (33)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (804 KB)

    Using some basic results in propagation theory, a single integral is derived which relates the channel delay power spectrum to the geometry and antenna patterns of the troposcatter link. Theoretical curves of delay power spectra and frequency correlation functions are presented for medium- and long-distance troposeatter links. View full abstract»

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  • Error Correction Code Performance on HF, Troposcatter, and Satellite Channels

    Publication Year: 1971, Page(s):781 - 789
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (823 KB)

    Four forward error correction techniques are examined and their performance compared on several real channels. Techniques of both adaptive and nonadaptive block and convolutional coding are examined. The Golay code is considered in a randomerror correcting mode and in an adaptive burst-random modes. Both versions employ interleaving as an added error correction aid. The adaptive convolutional code... View full abstract»

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  • A Simple Adaptive Equalizer for Efficient Data Transmission

    Publication Year: 1970, Page(s):5 - 12
    Cited by:  Papers (52)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1103 KB)

    A small and relatively inexpensive automatic equalizer has been developed for use with a vestigial sideband AM data set presently utilized to provide a high-speed Bell System voiceband data service. The equalizer uses a transversal filter structure comprising a tapped analog delay line with a variable-gain circuit associated with each tap. Its operation is adaptive in the sense that the tap-gain-a... View full abstract»

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  • Frequency Locked Loop FM Demodulator

    Publication Year: 1967, Page(s):518 - 524
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (700 KB)

    A new type of FM demodulator, the Frequency Locked Loop (FLL) is presented. The concept employed in this class of circuits is shown to be applicable in two forms. The first form is realized at the carrier, or IF frequency, to provide an FM detector that has the properties of not requiring a limiter preceding it and also of having a threshold superior to a normal FM discriminator limiter combinatio... View full abstract»

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  • Discrete-Time Least Squares, Minimum Mean Square Error, and Minimax Estimation

    Publication Year: 1966, Page(s):302 - 308
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (522 KB)

    A discrete-time signal estimation problem in which the input signal is represented by an expansion in terms of linearly independent functions is considered. After a set ofrnoisy measurements of the signal are made, a linear estimator of the function and/or its derivatives at some point in time, τ, is required. Due to systems or physical considerations or some other a priori conditi... View full abstract»

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  • Unique Word Detection in Digital Burst Communications

    Publication Year: 1968, Page(s):597 - 605
    Cited by:  Papers (22)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (759 KB)

    In a satellite time-division multiple-access (TDMA) system, the information is transmitted in bursts from the participating ground stations. In order to establish a time reference in each burst and to determine its origin, special code patterns called unique words (UW) are contained in the bursts. Reliable detection of the UW is the basis for keeping the stations in synchronism and providing high-... View full abstract»

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  • Nonlinear Equalization of Binary Signals in Gaussian Noise

    Publication Year: 1971, Page(s):1128 - 1137
    Cited by:  Papers (22)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (957 KB)

    A maximum a posteriori probability (MAP) approach is used to derive the optimal equalizer for binary signals transmitted at a constant rate over a dispersive and noisy channel. The optimal equalizer is shown to consist of a matched filter followed by a very complex nonlinear transversal filter. Various approximations are made to simplify the transversal filter. Thus the optimal linear equalizer an... View full abstract»

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  • Adaptive Variable-Length Coding for Efficient Compression of Spacecraft Television Data

    Publication Year: 1971, Page(s):889 - 897
    Cited by:  Papers (59)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (941 KB)

    An adaptive variable length coding system is presented. Although developed primarily for the proposed Grand Tour missions, many features of this system clearly indicate a much wider applicability. Using sample to sample prediction, the coding system produces output rates within 0.25 bit/picture element (pixel) of the onedimensional difference entropy for entropy values ranging from 0 to 8 bit/pixe... View full abstract»

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  • Filter Distortion and Intersymbol Interference Effects on PSK Signals

    Publication Year: 1971, Page(s):120 - 132
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1164 KB)

    The combined effects of filter distortion and the associated intersymbol interference on coherently detected biphase and quadriphase PSK signals are studied in white Gaussian noise. A determination is made of the system performance degradation from matched-filter detection resulting from the use of a linear channel model that focuses attention on the critical filters in the communication link. The... View full abstract»

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  • Optimization of the Performance of a Digital-Data-Transition Tracking Loop

    Publication Year: 1970, Page(s):686 - 689
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    The steady-state behavior of a data-transition tracking loop, used as a bit synchronizer in a phase-coherent receiver, is considered. Optimization of mean-square phase noise and mean time to first cycle slip is performed when the average power of the reference cross-correlating signal is constrained. It is shown that by adjusting the quadrature channel gain along with the integration interval, a s... View full abstract»

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  • Generalized Phase Comparators for Improved Phase-Locked Loop Acquisition

    Publication Year: 1971, Page(s):1142 - 1148
    Cited by:  Papers (7)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (736 KB)

    Phase-locked loops (PLL) with pulse-type (sawtooth) phase comparators find many applications in digital transmission systems. In this paper, the results available on the pull-in performance of the second-order PLL with sawtooth phase comparator are summarized. Then a generalized phase comparator, called a phase-and-frequency comparator, is shown to improve PLL acquisition performance significantly... View full abstract»

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  • Measurement of the Frequency Correlation Function of Fading Channels Using AM Stations as Signal Sources

    Publication Year: 1971, Page(s):9 - 13
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (451 KB)

    Measurements of the statistical characteristics of a proposed HF channel are usually required before such a channel is designed. These measurements require an elaborate test setup with test transmitters at the proposed transmitting sites. This work is therefore both time consuming and expensive, particularly when alternative locations are considered. This paper describes a method which allows the ... View full abstract»

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  • Companded Delta Modulation for Telephone Transmission

    Publication Year: 1968, Page(s):149 - 157
    Cited by:  Papers (25)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (866 KB)

    A new method of improving delta modulation with syllabic companding is presented. Companded delta modulation has a sort of syllabic companding function in its local decoder without depending on any nonlinear elements such as a variolosser. Analyses are made of the stationary companding law, dynamic response, overload characteristics, signal-to-noise ratio, overall transmission characteristics, etc... View full abstract»

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  • Analysis of Probabilistic Networks

    Publication Year: 1964, Page(s):38 - 40
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (350 KB)

    Three methods of analysis of a communication network in which the communication links are assigned finite probabilities of failure are presented. The methods are applied to the computation of the terminal reliabilities for all pairs of nodes. The terminal reliability between a pair of nodes is defined as the probability that there exists at least one path with these nodes as termini. The first met... View full abstract»

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Aims & Scope

This Transactions ceased publication in 1971. The current retitled publication is  IEEE Transactions on Communications.

Full Aims & Scope