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IRE Transactions on Communications Systems

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  • The Sum of Log-Normal Probability Distributions in Scatter Transmission Systems

    Publication Year: 1960, Page(s):57 - 67
    Cited by:  Papers (380)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (938 KB)

    The long-term fluctuation of transmission loss in scatter propagation systems has been found to have a logarithmicnormal distribution. In other words, the scatter loss in decibels has Gaussian statistical distribution. Therefore, in many important communication systems (e.g., FM), the noise power of a radio jump, or hop, has log-normal statistical distribution. In a multihop system, the noise powe... View full abstract»

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  • A Coherent Digital Amplitude and Phase Modulation Scheme

    Publication Year: 1962, Page(s):90 - 95
    Cited by:  Papers (48)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (503 KB)

    In this paper, we present a technique for a combination of amplitude and phase modulation for digital communication. This technique assumes phase coherence between transmitter and receiver. For purposes of analysis, we also assume baud synchronization. The technique involves the simultaneous and independent amplitude modulation of two carriers of the same frequency which are in quadrature with eac... View full abstract»

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  • Group Synchronization for Digital Transmission Systems

    Publication Year: 1962, Page(s):381 - 390
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (939 KB)

    Group synchronization systems with digital feedback are studied, which are particularly applicable for PCM systems. Group synchronization is used to determine the time origin of a sequence of binary signals by finding a specified deterministic pattern from a randomly modulated binary sequence. A statistical analysis is made on the recovery process of synchronization, which is a discrete-time rando... View full abstract»

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  • Reduction of Quantizing Noise by Use of Feedback

    Publication Year: 1962, Page(s):373 - 380
    Cited by:  Papers (76)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (669 KB)

    Many information transmission systems use a discrete (digital) channel. Since most input signals are continuous, the conversion cannot be accomplished without an error which, for many cases, may be considered to have the characteristics of white noise. A method has been suggested to reduce this error by using linear feedback around the quantizer to shape the noise spectrum. Each output sample will... View full abstract»

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  • On Optimal Diversity Reception, II

    Publication Year: 1962, Page(s):22 - 31
    Cited by:  Papers (56)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    In a previous paper the structure of the optimal multi-diversity receiver for a fading, noisy diversity channel was determined under the assumption that the memory of the receiver does not extend beyond the time interval of the signal currently being received. The probability of error for such a receiver is determined herein under the following assumptions: the channel is binary and symmetric; the... View full abstract»

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  • The Influence of Fading Spectrum on the Binary Error Probabilites of Incoherent and Differentially Coherent Matched Filter Recievers

    Publication Year: 1962, Page(s):160 - 168
    Cited by:  Papers (106)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (820 KB)

    Previous derivations of the influence of fading on the error probabilities of binary data transmission systems have assumed that the fading rate is so slow that fluctuations within a bit may be ignored. This slow fading assumption is removed in the present paper which derives general expressions for the binary error probabilities of incoherent and differentially coherent matched filter receivers e... View full abstract»

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  • Comparison of PSK vs FSK and PSK-AM vs FSK-AM Binary-Coded Transmission Systems

    Publication Year: 1960, Page(s):87 - 100
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1301 KB)

    The performance of phase shift keyed (PSK), frequency shift keyed (FSK), PSK amplitude modulation (PSK-AM), and FSK amplitude modulation (FSK-AM), systems are compared for binary coded transmission in the presence of additive white Gaussian noise. This performance is based on the relative probability of error, operating range, required system bandwidth, and system frequency instability. The import... View full abstract»

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  • A simplified diversity communication system for beyond-the-horizon links

    Publication Year: 1956, Page(s):50 - 55
    Cited by:  Papers (41)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (335 KB)

    For nearly a year the US Federal TelecomMunication Laboratories have had in operation a 900 mc beyond-the-horizon two-way link between the Nutley, New Jersey laboratories and Southampton, Long Island. Early results using PTM have already been reported. Briefly, an annual median path-loss some 20db greater than that predicted by Bullington was found, but the bandwidth was adequate for pulse modulat... View full abstract»

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  • Digital Computer Simulation for Prediction and Analysis of Electromagnetic Interference

    Publication Year: 1961, Page(s):148 - 159
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1248 KB)

    A digital computer simulation program is described for use by communications systems and equipment designers who must consider electromagnetic interference. The program determines the interference experienced by a test receiver in a signal environment resulting from its associated transmitter, a large deployment of potentially interfering transmitters, and by atmospheric and cosmic noise sources. ... View full abstract»

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  • Demonstration of Delay Distortion Correction by Time-Reversal Techniques

    Publication Year: 1957, Page(s):2 - 7
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (491 KB)

    Experiments relating to methods of correcting delay distortion by time-reversal have been made utilizing a slow-speed picture transmission system. The improvements in picture quality by phase correction of a 3 KC telephone loop 30.4 miles long and a 5 KC loop from Murray Hill, N. J., to Los Angeles, Calif., and back are demonstrated. The total distance that the signal was transmitted over the 5 KC... View full abstract»

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  • Performance of Combined Amplitude and Phase-Modulated Communication Systems

    Publication Year: 1960, Page(s):232 - 237
    Cited by:  Papers (36)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (539 KB)

    The performance of two types of digital phase-and amplitude-modulated systems is investigated for the high signal-to-noise ratio region. Approximate expressions for the probability of error and channel capacity of the more optimum of these two systems are compared with corresponding expressions for probability of error and channel capacity for a digital phase-modulated system. It is shown that the... View full abstract»

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  • An Impulse Interference Blanker for Communications Receivers

    Publication Year: 1956, Page(s):22 - 26
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (366 KB)

    The necessity for adequate and reliable communications for military operations has always existed. Today, with the trend toward everincreasing specializations of military forces and the continued growth of complex systems of radar, fighter control, etc. , this requirement has become more urgent. Since items of communication apparatus are often in close physical proximity to facilitate coordination... View full abstract»

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  • Theoretical Diversity Improvement in Multiple Frequency Shift Keying

    Publication Year: 1962, Page(s):177 - 184
    Cited by:  Papers (58)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    Multiple frequency shift keying (MFSK) is a modulation suitable for transmitting digital data under fading conditions. A quantitative analysis of MFSK-with-diversity is presented. The MFSK signals on the several diversity channels are presumed to be perturbed independently by Rayleigh fading and additive white Gaussian noise. Also, it is assumed that fading is slow and that envelope, cross-correla... View full abstract»

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  • Combined Digital Phase and Amplitude Modulation Communication Systems

    Publication Year: 1960, Page(s):150 - 155
    Cited by:  Papers (59)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (599 KB)

    The performance of phase modulation communication systems is investigated for the asymptotic case of a high signal-to-noise ratio. A simple and excellent approximation to the probability of error is derived for both coherent and phase-comparison demodulation. In addition, a simple expression is derived for the asymptotic degradation of phase-comparison demodulation. When the number of bits per sam... View full abstract»

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  • On the Optimum Performance of N-ary Systems Having Two Degrees of Freedom

    Publication Year: 1962, Page(s):185 - 192
    Cited by:  Papers (30)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (649 KB)

    A digital transmission system withnpossible transmitted symbols is considered. If the time between transmitted symbols is T0seconds and the bandwidth isW, thenpossible symbols correspond tonvectors in a2WT_{0}dimensional signal space. This paper considers the theoretical properties of a class of digital systems where the signal spac... View full abstract»

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  • The Telephone Channel in a Global Communications System

    Publication Year: 1961, Page(s):247 - 252
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    The nominal 4-kc telephone channel is by far the most dominant parameter of contemporary telecommunication networks. It is, directly or otherwise, underwritten by a world-wide investment of the order of fifty billion dollars. The engineering of present and future global communication networks must therefore provide for working with and into such channels, concomitantly with finding avenues out of ... View full abstract»

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  • Optical Communication During Hypersonic Re-Entry

    Publication Year: 1959, Page(s):68 - 70
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (323 KB)

    Communication during the re-entry of a space vehicle is a formidable problem because thermally-ionized gas in a shock wave surrounding such a vehicle absorbs the signal over the major portion of the radio spectrum. This paper describes some general features of re-entry communications. The entire electromagnetic spectrum is examined for selection of a suitable signal frequency. View full abstract»

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  • Analysis of SSB Power Amplifiers

    Publication Year: 1959, Page(s):53 - 57
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (525 KB)

    It is well known that one of the critical items in a single sideband (SSB) transmitter is the power amplifier with which are associated the basic problems of distortion, output power and plate dissipation. Tubes are available which may be used either as quasi-linear RF amplifiers operated class AB or B or as gridmodulated amplifiers operated class C. In the class-AB case, the SSB signal is introdu... View full abstract»

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  • Performance of Digital Phase-Modulation Communication Systems

    Publication Year: 1959, Page(s):3 - 6
    Cited by:  Papers (64)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (390 KB)

    This paper analyzes the performance of digital phase modulation systems in Gaussian noise and determines required signal-to-noise ratio as a function of the number of discrete phases and the desired error rate, under conditions of no fading. Both coherent detection with a locally-derived reference carrier and phase comparison detection are considered. The calculations show that multiphase modulati... View full abstract»

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  • Digital Phase Control Techniques

    Publication Year: 1960, Page(s):237 - 246
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (876 KB)

    An analysis of a partially digitized phase-locked loop usingZ-transform sampled data theory is presented. Responses are obtained at various junctions of the loop for both a step frequency input and for a sinusoidal frequency input. These responses are compared with the corresponding responses for an analog phaselocked loop. Stability criterion and root locus are determined. Effects of q... View full abstract»

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  • Predetection Diversity Combining with Selectively Fading Channels

    Publication Year: 1962, Page(s):32 - 42
    Cited by:  Papers (83)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (859 KB)

    The effective use of predetection (or IF) linear combining of diversity channels requires that all frequency components be added in = phase. In view of the time-variant phase characteristics of fading channels, some form of instantaneous phase correction must be provided prior to the diversity combining so that proper in-phase addition will result. If the instantaneous fading is not uniform over t... View full abstract»

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  • Economic Analysis of Communication Systems

    Publication Year: 1962, Page(s):416 - 421
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Modern communications systems are made up from a wide variety of building blocks and they utilize many different techniques. The system designer must first consider what equipments will meet the requirements of the user and should then determine the total cost, i. e., capital cost as well as operating cost of the possible choices. This paper discusses the technical factors to be considered and out... View full abstract»

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  • Analysis of a Phase-Modulation Communications System

    Publication Year: 1960, Page(s):221 - 227
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (599 KB)

    A communication system is analyzed which utilizes phase modulation (PM) and phase detection. The analysis shows that when the total radio frequency (RF) power level is significantly above the receiver threshold, a margin of safety exists which may be traded for additional signal-to-noise ratio (SNR) at the demodulated output of the receiver. In this respect the PM system is similar to FM communica... View full abstract»

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  • Communication in Air-Traffic Control

    Publication Year: 1958, Page(s):27 - 29
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (293 KB)

    One of the major obstacles to the solution of the air-traffic control problem is the limitation imposed on information flow by the outdated air-to-ground communication system now in use. A study of the present system and its deficiencies gives a set of requirements for a communication system that will assist materially in the solution of the air-traffic control problem. Another set of communicatio... View full abstract»

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  • Information Transmission Rate at Very Low Signal and Noise Power

    Publication Year: 1962, Page(s):407 - 415
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    Assuming very low signal and noise power at the receiver, the transmission rate of information is calculated for peak power and average power limitation. These calculations are made using the assumption that the signal energy received is a Poissondistributed random variable. The result is compared with that in the high-power case. View full abstract»

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  • Binary Error Rates in Fading FDM-FM Communications

    Publication Year: 1961, Page(s):206 - 214
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (992 KB)

    This paper discusses the transmission of binary data over a fading frequency-division multiplexed FM (FDM-FM)radio system. The important results are convenient design formulas for binary error rate in terms of the symbol duration, the IF bandwidth, the per channel rms frequency deviation, the average received carrier-to-noise ratio, and the particular types of binary detection and diversity combin... View full abstract»

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  • A Synchronized Pulse Communication System with Pseudorandom Interpulse Period

    Publication Year: 1962, Page(s):109 - 113
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (576 KB)

    The security of a pulse type communication system can be improved by the incorporation of an element of randomness in the time of transmission. A system is simulated in which a remote receiver is caused to be gated on at apparently random intervals which are in synchronism with the arrival of the signal from the controlling local transmitter. The time of transmission is not random, but is determin... View full abstract»

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  • Coexistence of Celestial and Terrestrial Communications

    Publication Year: 1961, Page(s):460 - 462
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    Artificial satellite repeaters will revolutionize radio communication by permitting the use of microwaves over long paths. There will also be a continuing and mounting need for terrestrial applications of microwave services over relatively short distances. Achieving coexistence between these long- and shortdistance systems will conserve and enhance the utilization of the microwave spectrum. Extens... View full abstract»

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  • Effects of Impulse Noise on Digital Data Transmission

    Publication Year: 1961, Page(s):355 - 361
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (894 KB)

    This paper presents the basic characteristics of impulse noise and its effects on various types of binary data transmission systems. The sources and properties of such impulsive noise, in contrast to Gaussian noise, are discussed. A method is described for the experimental comparative evaluation of bit error rates in the presence of additive impulse noise. The method is shown to permit unique comp... View full abstract»

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  • Practical and Theoretical Design Cosiderations for Bridge Negative Feedback Amplifiers in Carrier Telephony

    Publication Year: 1957, Page(s):26 - 31
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (481 KB)

    The problem of providing proper impedance matching for interconnecting circuitry in Carrier Telephony Systems is of first-order importance. Transmission branches that contain nonpassive elements, such as amplifiers, are of particular concern and thus require special treatment. Bridge feedback amplifiers employing a hybrid output transformer offer outstanding advantages as a solution. Basic design ... View full abstract»

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  • Simple Methods for Designing Troposcatter Circuits

    Publication Year: 1960, Page(s):193 - 198
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (515 KB)

    As troposcatter circuits come more and more widely into use, there is a need for simple and reasonably accurate design methods for routine use, since the speed of obtaining a suitable design is sometimes of the utmost importance. This paper attempts to present such a method, derived primarily from experimental data, but with occasional reliance upon theoretical calculations. Certain essential desi... View full abstract»

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  • Performance of Error-Correcting Codes

    Publication Year: 1962, Page(s):72 - 85
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1132 KB)

    Binary decoding of relatively short codes corrupted by Gaussian noise or pulse interference has been considered in applications for which the minimum useful information block length is unity, equal to the information bit capacity of a code, or equal to an integral multiple of the information capacity of a code. The following results pertain to applications which are further characterized by the pe... View full abstract»

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  • Results of propagation test at 505 Mc and 4090 Mc on beyond horizon paths

    Publication Year: 1956, Page(s):104 - 111
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    This paper summarizes the results of some radio propagation tests that were conducted for a full year in Newfoundland starting in late 1953. A more detailed paper on these results was declassified in time to be included in the October 1955 issue of the Proceedings of the IRE. The Newfoundland tests were sponsored by the US Air Force to obtain information for engineering beyond horizon radio relay ... View full abstract»

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  • Practical consideration for forward scatter applications

    Publication Year: 1956, Page(s):28 - 31
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (542 KB)

    It is now possible to provide communications with high reliability factors in geographical areas which are resistant to the more conventional high-frequency radio. For the past two years, the US Air Force has been operating an ionospheric scatter system (FPIS) between Loring AFB, Maine, USA, and Thule AFB, Greenland. Relay stations in this system are located at Goose Bay, Labrador, Canada and Sond... View full abstract»

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  • Digital Computer Simulation of Communications Networks

    Publication Year: 1962, Page(s):118 - 125
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (809 KB)

    In planning large scale communications networks, the systems engineer must define the best mix of system trunking assignments, switching logic, and system operating policies. Field tests are not usually a practical method of evaluating network performance as the above design parameters are changed-particularly if the networks are complex and if many operating personnel are involved. An alternative... View full abstract»

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  • Preliminary Study of a Miniature Underwater Cable System

    Publication Year: 1961, Page(s):159 - 164
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB)

    Certain aspects of feasibility of a miniature submarine cable-transmission system have been studied. The system is small and light, and designed for use in military applications as an expendable item where submarine cables of conventional design would be uneconomical. It weighs about 125 pounds per mile, transmits 1.35 million pulses per second of a pulse-code modulated (PCM) signal, and is powere... View full abstract»

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  • Techniques for Comparing Modulation Methods for Data Transmission over Telephone Channels

    Publication Year: 1961, Page(s):239 - 243
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (878 KB)

    A program has been initiated for study of complete data communication systems by a general purpose analog computer. Complete PM and FM systems including transmitter, receiver, and channel have been simulated. Illustrative results and a discussion of criteria of performance are presented. View full abstract»

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  • Radio Link Communication Reliability: A Three-Part Design Problem

    Publication Year: 1959, Page(s):47 - 52
    Cited by:  Papers (53)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2313 KB)

    The degree of reliability required for equipment used in a global communications system must be designed into the equipment from the inception of the original design specification and implemented through all stages of development, procurement, production, and testing. The design of a system based on three basic concepts, redundancy, rugged circuit design, and complete monitoring and alarm faciliti... View full abstract»

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  • High-Speed Frequency-Shift Keying of LF and VLF Radio Circuits

    Publication Year: 1957, Page(s):29 - 42
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1904 KB)

    Present VLF transmitters are limited in transmission speed to approximately 20 words per minute because of the bandwidth limitations of the High-Q antenna circuit. To permit an increase in transmission speed, a unique method has been developed which makes use of the variation of reactance of the antenna circuit in synchronism with frequency shift modulation of the carrier. The method makes possibl... View full abstract»

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  • Design Considerations for Space Communication

    Publication Year: 1959, Page(s):232 - 240
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1225 KB)

    With the advent of Russian and American artificial earth satellites, the use of such vehicles for communication purposes has been the subject of considerable study both by military and commercial organizations in the communications field. The purpose of this paper is to delineate the problems involved in space communication, the assumptions that must be made and the technical limitations which det... View full abstract»

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  • Multiple Echo Distortion in Frequency-Modulation, Frequency-Division-Multiplex Trunk Radio Systems

    Publication Year: 1962, Page(s):61 - 71
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (860 KB)

    This paper is concerned with intermodulation distortion in FM, FDM trunk radio systems due to a number of echoes of differing amplitudes and delay times. General formulas are developed, and applied to the case of a 960-channel system subjected to distortion due to echoes from flanges in waveguide runs. Examples considered are 100- and 200-ft runs of RG-50/U waveguide, in 10-ft sections, for use in... View full abstract»

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  • Reduction of Adjacent-Channel Interference from On-Off Keyed Carriers

    Publication Year: 1956, Page(s):41 - 58
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1229 KB)

    The well-known reduction of sideband interference by filtering in the keying circuit of transmitter is examined in detail to determine the amounts of sideband reduction which can be obtained with practical filters and still retain desirable keying waveforms. It is found that reductions in interfering bandwidths by 1OO to 1 or more over unfiltered keying at sideband levels of 70 db or more below th... View full abstract»

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  • Air-to-Ground Meteoric Scatter Communication System

    Publication Year: 1960, Page(s):113 - 133
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (3929 KB)

    Several point-to-point systems have demonstrated successful communications while employing propagation via meteor trail reflections at very high frequencies. However, few systems have been able to control the output error rate in the presence of sporadicEand auroral phenomenon. Nevertheless, early results clearly indicated the strong potential of the meteor mode for extremely reliable c... View full abstract»

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  • Prelimiting Bandpass Filtering on Fading Radio Circuits

    Publication Year: 1959, Page(s):42 - 46
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (601 KB)

    On channels subject to multipath propagation, the prelimiting bandpass filtering technique is shown to be a factor of great importance in determining the over-all performance. Minimum-loss, fiat-topped filters create serious transient effects which add greatly to the error rate in data transmission. Because of adjacent channel requirements, an over-all Gaussian response is not applicable. A practi... View full abstract»

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  • The Theory of FM Demodulation with Frequency-Compressive Feedback

    Publication Year: 1962, Page(s):226 - 245
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2307 KB)

    The application of frequency-compressive feedback around an amplitude-insensitive FM demodulator promises important reductions of distortion and noise sensitivity in the demodulation of wide-band FM signals. In this paper, the basic theory of FM demodulation with frequency-compressive feedback (FCF) is presented after a brief discussion of the concept of noise threshold and of the usefulness of th... View full abstract»

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  • Reduced-Time Facsimile Transmission by Digital Coding

    Publication Year: 1961, Page(s):215 - 222
    Cited by:  Papers (8)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1025 KB)

    The growing importance of digital communication links has resulted in a family of coding methods designed to achieve reduced-time digital facsimile transmission. This paper reports on a study of the effectiveness and feasibility of one of these methods, Run Length Coding (RLC). RLC is a well-known digital method in which the area and shade of the copy are quantized to form a mosaic pattern. Neighb... View full abstract»

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  • Reduction of Adjacent-Channel Interference Components from Frequency-Shift-Keyed Carriers

    Publication Year: 1958, Page(s):39 - 47
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (869 KB)

    The abrupt changes in frequency associated with binary modulation generate sideband components which frequently interfere with services in adjacent channels. Reductions in interfering bandwidths of 10 to 1 or greater over unfiltered keying at sideband levels 80 db or more below the unmodulated carrier are possible by the use of relatively simple filters in the keying circuit of frequency-shift-key... View full abstract»

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  • Development Trends in USAF Global Communications Systems

    Publication Year: 1959, Page(s):241 - 248
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (861 KB)

    This paper briefly summarizes one initial development approach for the 1962-1965 USAF Global Communications Systems. A brief review is given of some of the early communications systems work and the present design philosophy for the 600-voice bandwidth channel, 6000-mile trunk system is discussed. Specific requirements of the ground-based Air Force common-user system are listed and developments int... View full abstract»

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  • Constant-Ratio Code and Automatic-RQ on Transoceanic HF Radio Services

    Publication Year: 1960, Page(s):72 - 75
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (506 KB)

    Historical development, of present-day commercial teleprinter services, is briefly tabulated according to dates of significant advances. The 7-unit form of basic constant-ratio code is given, and its advantages explained; indicative values of improvement are tabulated. A general description of the Automatic-RQ method and system-rather than specific designs-is given. Commercial application and grow... View full abstract»

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  • Analysis of a PCM System Employing a PPM Vernier

    Publication Year: 1961, Page(s):342 - 349
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (697 KB)

    The upper limit to the output SNR of sampled-data PCM systems is set by the quantization noise. The present study is concerned with a method of overcoming this limitation by employing time shifting of the PCM pulse groups so as to constitute an analog encoding of the difference between the sample amplitude and the nearest quantization level. Thus PCM is introduced to serve as a vernier to PPM. For... View full abstract»

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Aims & Scope

This Transactions ceased publication in 1962. The current retitled publication is  IEEE Transactions on Communications.

Full Aims & Scope