IEEE Conference on Military Communications

Sept. 30 1990-Oct. 3 1990

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Displaying Results 1 - 25 of 245
  • MILCOM 90. A New Era. 1990 IEEE Military Communications Conference. Conference Record (Cat. No.90CH2831-6)

    Publication Year: 1990
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    Freely Available from IEEE
  • Video quality gradient measures for digital networks

    Publication Year: 1990, Page(s):289 - 296 vol.1
    Cited by:  Papers (1)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (556 KB)

    Two of the most significant video quality degradations produced by digital compression in codecs are image blurring and distortion of edges in areas of motion. These degradations become more evident at reduced transmission rates. Two objective measures of video quality, one based on Laplacian and the other on Sobel gradient operators, are proposed. They are validated with desktop video teleconfere... View full abstract»

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  • Satellite system for tactical MILSATCOM applications

    Publication Year: 1990, Page(s):278 - 288 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (552 KB)

    The communication requirements for continuous MILSATCOM service can be met by augmenting the current and planned MILSATCOM systems with a functionally simple, low-cost, maneuverable, user-dedicated satellite constellation for tactical applications (TACSAT) whose payloads are under direct control of the theater Commander in Chief (CINC). A perspective on moderately hardened, low-cost SHF and EHF sa... View full abstract»

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  • Differential modulation and demodulation of multi-frequency digital communications signals

    Publication Year: 1990, Page(s):273 - 277 vol.1
    Cited by:  Papers (1)  |  Patents (36)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    Multiple-frequency modulation (MFM) is a bandwidth-efficient digital communication signaling technique that may be used effectively in mobile satellite communications links. Algorithms for generating and demodulating differentially encoded multifrequency quadrature phase shift keyed (MFQPSK) signals using discrete Fourier transform (DFT) techniques are discussed. The theory and a prototype system ... View full abstract»

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  • Handling the RF output of high-power TWTAs in spacecraft

    Publication Year: 1990, Page(s):188 - 192 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    The radiated power demands of Ku-band communications satellites are currently being met by a generation of high-efficiency helix traveling wave tubes (TWTs) capable of output powers in the range of 50 to 230 W. The problems encountered by the RF output network in handling the power of many such channels are discussed. The importance of testing is stressed, and illustrations are drawn in p... View full abstract»

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  • Experimental measurements on the two-tone method of fine-time uplink synchronization for FH SATCOM signals

    Publication Year: 1990, Page(s):268 - 272 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    The two-tone method of fine-time uplink synchronization for a frequency-hopped (FH) spread-spectrum satellite communication system was implemented in a hardware-based laboratory experiment using an analog surface acoustic wave spectrum analyzer. The method produces a timing-error estimate. In order to correct the bias and inconsistency in this estimate, a technique called bias reduction is used. M... View full abstract»

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  • Multipactor breakdown and passive intermodulation in microwave equipment for stellite applications

    Publication Year: 1990, Page(s):181 - 187 vol.1
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB)

    The phenomena of multiplication and passive intermodulation (PIM) as applied to passive microwave equipment for satellite applications is addressed. A brief summary of PIM and ways to prevent it are given. High-power measured data for a range of microwave equipment and subsystems is included. The measured power levels represent the state-of-the-art for high-power output circuits required for commu... View full abstract»

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  • Performance evaluation of land mobile satellite system under vegetative shadowing using differential multiple TCM and QPSK

    Publication Year: 1990, Page(s):263 - 267 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    A comparative analysis by computer simulation of the land mobile satellite system (LMSS) is presented for the uncoded quadrature phase shift keying (QPSK), rate 2/3 8-PSK trellis coded modulation (TCM), and rate 4/6 multiplicity 2 8-PSK TCM schemes. An analytical model is used for simulating the fading channel. The simulation results show that under Rayleigh fades, the TCM designed for the fading ... View full abstract»

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  • Frame synchronization for a channel with different data rates

    Publication Year: 1990, Page(s):176 - 180 vol.1
    Cited by:  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    In some communication links, different data rates are used at different times on the same channel and each is assigned a separate frame synchronization (sync) marker. The frame search is completed within a finite number of frame intervals once both phase-lock and bit-sync are achieved because the incoming data rate can change. The probability of failure to frame-lock, and an upper bound of probabi... View full abstract»

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  • Theater/user-dedicated communications satellite system concept

    Publication Year: 1990, Page(s):258 - 262 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (476 KB)

    The results of an ongoing study of a theater/user-dedicated communications satellite system concept, which would augment the existing satellite systems (DSCS and MILSTAR), are presented. The system attempts to satisfy a user requirement in incremental amounts. The study entails requirements analysis, concept exploration, and cost and risk analysis. User requirements are determined from contact wit... View full abstract»

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  • Selfconsistent model for pseudomorphic MOSFETs

    Publication Year: 1990, Page(s):486 - 490 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    A self-consistent charge control and current-voltage (I V) characteristics are presented for a pseudomorphic MODFET (AlGaAs/InGaAs/AlGaAs). Poisson's and Schrodinger's equations are solved self-consistently to calculate the areal charge distribution n s in the quantum well (QW). For simplicity, the QW formed in InGaAs is approximated by three straight lines. T... View full abstract»

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  • Software for the analysis of microwave operational scenarios

    Publication Year: 1990, Page(s):456 - 460 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    Microwave operational scenario evaluation software (MOSES) for IBM-PC-compatible computers was developed to analyze propagation effects up to 1000 GHz. The purpose of the software is to provide a uniform, user-friendly interface to a great variety of analysis programs so that it is not necessary to learn to use different software packages each time a new problem is analyzed. Applications to be ana... View full abstract»

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  • Interference suppression using a SAW-based adaptive filter

    Publication Year: 1990, Page(s):970 - 974 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The structure and performance of a transversal filter interference suppressor that has been constructed using a surface acoustic wave (SAW) delay line are described. The delay line operates at a center frequency of 300 MHz and has eight equally spaced taps with an intertap delay of 150 ns. In the programmable mode, the tap weights are externally controllable, and in the adaptive mode, the tap weig... View full abstract»

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  • Direct sequence spread spectrum serial acquisition in a nonselective and frequency selective Rician fading channel

    Publication Year: 1990, Page(s):171 - 175 vol.1
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The mean acquisition time performance of a straight, serial-search direct-sequence spread spectrum (DS-SS) acquisition system, operating in nonselective and frequency-selective Rician fading channels is analyzed. The system was proposed by Polydoros and Weber (1984), and its performance is analyzed for a nonfading channel, at which all the cells that fall under hypothesis Ho ar... View full abstract»

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  • VLSI development of a global memory interface controller

    Publication Year: 1990, Page(s):254 - 257 vol.1
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    A high-speed global bus chip used for interprocessor communications is developed. This 2.0 μm CMOS standard cell integrated circuit is targeted for use in digital signal processing (DSP) applications where global memory resources are required. The global memory interface controller (GMIC) contains both a bus arbitration unit to prevent bus contention and a memory controller to access the addres... View full abstract»

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  • Shaped PSK in a digital modem with direct digital synthesis

    Publication Year: 1990, Page(s):86 - 92 vol.1
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    Performance data for the MD-1269A Multipurpose Modem modulator are presented with emphasis on spectrally efficient phase shift keying (PSK). Attention is focused on power spectral containment within 5-kHz and 25-kHz communication satellite channels, measured relative interference levels in adjacent channels, vector rotation effects, and spectral performance as a function of shaping factor. The mod... View full abstract»

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  • 35-GHz monolithic GaAs FET power amplifiers

    Publication Year: 1990, Page(s):483 - 485 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    A state-of-the-art 35-GHz monolithic GaAs power amplifier, based on metal semiconductor field-effect transistor (MESFET) technology, is developed for millimeter-wave communications and seeker applications. Both single-ended and balanced amplifier configurations, with on-chip DC-block and bias networks, are designed and evaluated. A cascaded four-stage amplifier exhibited 14.6 dB of linear gain and... View full abstract»

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  • Advances in line-of-sight link design for DoD applications

    Publication Year: 1990, Page(s):449 - 455 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    A comprehensive line-of-sight (LOS) link design program for Department of Defense (DoD) applications is discussed. A brief description of the digital LOS radio link design process as it is codified in a link design program is provided. This program provides a unified and complete methodology for link design, based on a mix of documented approaches. The general design process and program structure ... View full abstract»

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  • A new receiver operating in multiple access interference related to the near far problem

    Publication Year: 1990, Page(s):966 - 969 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    A receiver designed for direct sequence code division spread spectrum multiple access (DS/SSMA) systems is described. The interference is modeled by additive white Gaussian noise (AWGN) and one spread spectrum signal introduced by a multiple access user. It is assumed that the interfering user is near to the receiver and appears as a strong signal at the receiver's front end. This constellation is... View full abstract»

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  • Acquisition time distribution for Z search strategies in spread spectrum receivers

    Publication Year: 1990, Page(s):166 - 170 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    An analysis of the acquisition process for Z serial-search direct-sequence spread spectrum receivers is presented. Using strictly time-domain techniques, equations for the acquisition time probability density function and mean are derived. Probabilities for small acquisition time may be calculated exactly, while larger times require Gaussian approximation to reduce computation time. The a... View full abstract»

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  • Realization of a monochip Viterbi decoder in ASIC technology

    Publication Year: 1990, Page(s):249 - 253 vol.1
    Cited by:  Papers (2)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB)

    An ASIC realization of a Viterbi decoder is presented for the convolutional code of rate 1/2 and constraint length 7 (generator polynomials 133 and 171) and the code derived from it by puncturing to provide a code of rate 3/4, or by reuse of the same polynomials to get codes of rate 1/4 and 1/8. The technology is CMOS 1.5 μm, and the chip size is 14×14 mm2. It contains about 45... View full abstract»

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  • On the weight distributions of m-sequences in AWGN

    Publication Year: 1990, Page(s):81 - 85 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    An analysis and simulation is performed on the effect of additive white Gaussian noise (AWGN) on the weight distribution of the cross-correlation function between two maximal-length sequences (m-sequences) for direct-sequence spread-spectrum modulation, with specific examples cited for the m-sequences of linear span eight. The decimation, cross-correlation, and weight distribution properties of m-... View full abstract»

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  • Statistical analysis of the Wigner-Ville distribution with applications to wideband detection

    Publication Year: 1990, Page(s):825 - 829 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    A time-frequency statistical description of the Wigner-Ville distribution of random processes that exploits the statistical parameters constituting the Karhunen-Loeve expansion of the original time process is introduced. This provides a method for constructing Wigner-Ville-based detector structures that are of analytical handiness. As an illustration of the utility of this statistical analysis, an... View full abstract»

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  • Joint echo canceller/equalizer and timing recovery for high speed full duplex baseband transmission systems

    Publication Year: 1990, Page(s):776 - 780 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    The interaction between echo cancellation/equalization and timing recovery is analyzed, a complete simulation of a high-speed full-duplex digital subscriber loop system is reported, and issues related to the support of multirate sampling and feedback are discussed. The simulation results suggest that the number of equalizer (EQ) training symbols must be reduced, rather than the number of echo canc... View full abstract»

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  • Advanced HF ant-jam network architecture

    Publication Year: 1990, Page(s):207 - 211 vol.1
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (432 KB)

    The Hughes HF2000 system was developed for military communications using a flexible architecture which utilizes a wideband RF front-end and extensive digital signal processing. The HF2000 antijamming (AJ) mode was field tested via an HF skywave path between Fullerton, CA and Carlsbad, CA (~100 miles), and it was shown that reliable fast frequency-hopping data transmission is feasible at 2400 bit/s... View full abstract»

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