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Military Communications Conference, 1989. MILCOM '89. Conference Record. Bridging the Gap. Interoperability, Survivability, Security., 1989 IEEE

15-18 Oct. 1989

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Displaying Results 1 - 25 of 169
  • MILCOM 89. Bridging the Gap. Interoperability, Survivability, Security. Conference Record. 1989 IEEE Military Communications Conference (Cat. No.89CH2681-5)

    Publication Year: 1989
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    Freely Available from IEEE
  • Millimeter-wave low-noise amplifiers-an overview

    Publication Year: 1989, Page(s):725 - 729 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    The contributions to system noise, including those external to the receiving system, are discussed, with emphasis on the 30-100-GHz range and the latest results obtained with high-electron-mobility transistors (HEMTs). The different types of HEMTs are defined, and a table showing the achievable noise figures of multistage low-noise amplifiers as a function of frequency is presented. An example of ... View full abstract»

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  • Equalization of differentially coherent QPSK operating over slowly fading Rician channels

    Publication Year: 1989, Page(s):720 - 724 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    The effects of a simple equalizing system on the performance of a differentially coherent QPSK (quaternary phase-shift-keying) system operating over selectively and slowly fading Rician channels are analyzed. The proposed receiver consists of linear matched filters cascaded with linear equalizers and postdetection diversity combining systems. The bit-error probability, which is the performance mea... View full abstract»

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  • Bit by bit error rate performance of land mobile satellite system (LMSS) under fading channel using QPSK/MSK

    Publication Year: 1989, Page(s):715 - 719 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    Aspects of error performance of the land mobile satellite system (LMSS) using QPSK (quaternary phase-shift keying) and MSK (minimum shift keying) under fading channel conditions have been studied. In contrast to the sole use of average bit-error rate (BER) as a performance measure, bit-by-bit-error rates are calculated for the sequence of transmitted data under various fading conditions by compute... View full abstract»

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  • RNS-based GaAs signal processing system

    Publication Year: 1989, Page(s):615 - 619 vol.2
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    Residue number system (RNS) finite-impulse-response (FIR) digital filter and discrete Fourier transform (DFT) systems are designed with GaAs components. Estimated processing bandwidths up to 300 MHz can be obtained using existing GaAs parts. By incorporating an application-specific integrated circuit (ASIC) into the system, processing bandwidths in excess of 400 MHz are possible. A discussion of t... View full abstract»

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  • Throughput optimization in single commodity slotted ALOHA multi-hop packet radio networks

    Publication Year: 1989, Page(s):377 - 382 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    The authors investigate the maximum throughput that can be supported between a pair of nodes in a multihop packet radio network using slotted ALOHA. The optimization problem can be formulated as a nonlinear programming problem. The authors study different topologies where source and destination are connected with a number of independent paths and consider the cases in which the flow from source to... View full abstract»

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  • A tone-aided dual vestigial sideband system for digital communications on fading channels

    Publication Year: 1989, Page(s):709 - 714 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    A spectrally efficient tone-aided dual vestigial sideband (TA/DVSB) system for digital data communications on fading channels is presented and described analytically. This PSK (phase-shift-keying) system incorporates a feed-forward, tone-aided demodulation technique to compensate for Doppler frequency shift and channel- induced, multipath fading. In contrast to other tone-in-band-type systems, rec... View full abstract»

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  • Analog filter design for improved performance in an atmospheric noise environment

    Publication Year: 1989, Page(s):577 - 580 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    It is shown that several transitional low-pass characteristics can be converted accurately to realizable bandpass crystal filters for the very narrowband case (0.17% relative bandwidth and smaller). Ordinary design techniques such as Dishal's are applicable up to 5% relative bandwidth; but beyond that, up to about 50%, special techniques like bandwidth scaling and center frequency translation of a... View full abstract»

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  • Error correcting unit for slow frequency hopping radio stations

    Publication Year: 1989, Page(s):179 - 183 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    The design, features, and implementation of an error-correcting unit (codec) for combat net radio systems are described. Extensive measurements have been made on the developed unit, and it has shown very good error-correcting capabilities. Bit-error rates and block-error rates have been measured for different jamming situations. Measurements have been made for user rates of 2400, 1200, 600, and 30... View full abstract»

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  • Digital beamforming techniques and processors based on quadratic residue number system techniques

    Publication Year: 1989, Page(s):609 - 614 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (444 KB)

    A very-high-performance digital beamforming processor has been implemented using ASICs (application-specific integrated circuits) fabricated in readily available commercial CMOS process technology by using QRNS (quadratic residue number system) techniques. The chips have been designed and tested to operate at 50 MHz. The brassboard processor is capable of providing either four simultaneous beams, ... View full abstract»

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  • A technique for detecting unknown weak signals in noise that is not additive white Gaussian

    Publication Year: 1989, Page(s):370 - 376 vol.2
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    A general spectrum-analysis-based approach to the problem of detecting the presence of unknown weak signals in noisy observations is developed. The weak signal assumption enables exploitation of familiar results from the theory of local optimality, from which correlation-based detectors for the presence of known weak signals in additive independent and identically distributed (IID) noise have been... View full abstract»

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  • A DS spread spectrum RAKE receiver with narrowband interference rejection capability: operation in fading channels

    Publication Year: 1989, Page(s):704 - 708 vol.3
    Cited by:  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    The authors analyze the performance of a modified noncoherent direct-sequence differential-phase-shift-keying (DS/DPSK) spread-spectrum RAKE receiver which operates under the conditions of a frequency-selective fading channel with narrowband tone interference. Interference rejection capability is added to a basic noncoherent RAKE receiver by including a front-end prewhitening filter. For the case ... View full abstract»

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  • Millimeter-wave HEMT technology

    Publication Year: 1989, Page(s):744 - 748 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    The authors report the development of short gate-length (0.15-0.25-μm) HEMTs (high-electron-mobility transistors) with state-of-the-art noise and power performance. The three families of HEMTs-conventional GaAs/AlGaAs, pseudomorphic, and InP-based-are described and compared. The InP HEMTs offer the lowest noise figure: device noise figures of 0.3 dB at 18 GHz and 1.4 dB at 94 GHz have been meas... View full abstract»

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  • Diversity reservation ALOHA

    Publication Year: 1989, Page(s):402 - 407 vol.2
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB)

    A multiaccess protocol suitable for packet-switched satellite broadcast channels is considered. The proposed protocol, called diversity reservation ALOHA (DRA), combines the essential features of announced retransmission random access (ARRA), reservation ALOHA, and diversity ALOHA to achieve the goals of improved delay-throughput characteristics and high channel utilization. Two versions of DRA pr... View full abstract»

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  • Cutoff rate for channel having precoding, continuous-phase modulation, and differential detection

    Publication Year: 1989, Page(s):764 - 768 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    The authors consider encoded M-ary continuous-phase-modulated signaling with suboptimal demodulation-decoding, a transmission scheme useful when bandwidth and power are limited. Demodulation is via differential detection, and decoding is optimal. It is assumed that additive white Gaussian noise is the only disturbance. A form of precoding that undoes, before it is done, the correlation am... View full abstract»

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  • A robust adaptive filtering algorithm with variable step size

    Publication Year: 1989, Page(s):526 - 530 vol.2
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    The authors present a variable-step adaptive filtering algorithm (VS-NLMS) that is robust in the presence of interference. An estimated cross-correlation coefficient between the input reference signal and the error signal is used as the variable step size. Compared with the conventional fixed-step adaptive filtering algorithm (NLMS), the VS-NLMS algorithm can achieve much lower misadjustment noise... View full abstract»

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  • Application of simulation based analysis to receiver design for operation in impulsive atmospheric noise

    Publication Year: 1989, Page(s):570 - 576 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    The author illustrates a Monte-Carlo procedure that simulates impulsive noise bursts by using a set of characteristics that represents a realistic range of values. It is expected that many non-Gaussian varieties of noise may be dealt with numerically in a similar manner, following experimental determinations of the most appropriate parameter values for use in the noise model. A limited sample case... View full abstract»

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  • Stanford Telecom VLSI design of a convolutional decoder

    Publication Year: 1989, Page(s):171 - 178 vol.1
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (532 KB)

    The authors describe the novel hardware and speed-efficient architectural features of a recent Stanford Telecom VLSI implementation of a 20-Mb/s convolutional decoder using 1.5-μm CMOS technology. The chip offers a selection of convolutional codes, including the (2,1) K=7 code commonly used in satellite communications, high-rate punctured versions of the code, and a (2,1) K=6 ... View full abstract»

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  • The application of core functions to residue number system signal processing

    Publication Year: 1989, Page(s):604 - 608 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    The authors briefly outline core-based residue number system (RNS) processing. An RNS adaptive array processor using Choleski decomposition and forward elimination/back substitution is described as an example. The RNS adaptive processor was simulated, and preliminary results that indicate the feasibility of the approach are presented. The most significant of these results is the ability of the eig... View full abstract»

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  • Limitations on the detectability of spread-spectrum signals

    Publication Year: 1989, Page(s):364 - 369 vol.2
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    The standard analysis of the radiometric detectability of a spread-spectrum signal assumes a background of stationary white Gaussian noise whose power spectral density can be measured very accurately. This assumption yields a fairly high probability of interception, even for signals of short duration. Using a generalization of the detection scenario, the authors demonstrate that realistic detectio... View full abstract»

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  • Predeinterleaving soft decision performance for MFSK detection on the Rayleigh fading channel

    Publication Year: 1989, Page(s):697 - 703 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    The authors consider MFSK (M-ary frequency shift keying) communications systems that achieve time diversity by using convolutional interleaving of L repeated chips per symbol. Two system processing options are investigated. The first is that of conventional deinterleaving followed by demodulator magnitude accumulation and soft decision bit recovery. The second is predeinterleaver soft dec... View full abstract»

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  • High efficiency autotrack feed

    Publication Year: 1989, Page(s):316 - 320 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    A high efficiency autotrack feed series that uses a tracking mode coupler to generate track error signals has been developed. The mode coupler allows the use of a corrugated feed horn in doubly shaped or Cassegrain geometries to achieve extremely high overall antenna efficiencies. The extremely low loss in the mode coupler allows the incorporation of the autotrack function in an antenna system wit... View full abstract»

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  • Shipboard HF interference: problems and mitigation

    Publication Year: 1989, Page(s):106 - 110 vol.1
    Cited by:  Papers (4)  |  Patents (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    Cosite HF interference on shipboard is becoming more acute because of emerging requirements that call for simultaneous transmissions with antijam and frequency-hopping formats. The authors quantify several interferers and suggest ways to improve transmission. They include self-steering, low-level filters, linearized transmitters, intermod cancellation, improved transmitter-antenna coupling, time-d... View full abstract»

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  • A new pseudo-random interleaving for antijamming applications

    Publication Year: 1989, Page(s):6 - 10 vol.1
    Cited by:  Papers (1)  |  Patents (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    The authors define a pseudorandom interleaver whose minimal distance is nearly the same as that of a periodic interleaver of the same size. The distance between two symbols of the same code word is not constant, and symbols are selected pseudorandomly inside the interleaving register. This makes it proof against attacks by intelligent jammers. The interleaver uses a matrix read and written at the ... View full abstract»

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  • V-band monolithic two stage HEMT amplifiers

    Publication Year: 1989, Page(s):739 - 743 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    Two different types of HEMT (high-electron-mobility transistor) monolithic low-noise amplifiers (LNAs) using AlGaAs/GaAs and pseudomorphic InGaAs/GaAs materials have been developed and have demonstrated excellent performance at 60 GHz. These monolithic LNAs have achieved noise figures of 5 dB, as well as associated gains of 11 dB. These two-stage circuits both utilize 0.2×60-μm HEMT devic... View full abstract»

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