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

Date 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
  • Doped-channel heterojunction structures for millimeter-wave discrete devices and MMICs

    Publication Year: 1989 , Page(s): 730 - 734 vol.3
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (272 KB)  

    AlGaAs/InGaAs/GaAs-type heterostructures with one or two channels have been used to fabricate both discrete devices and monolithic amplifiers for millimeter-wave operation. The authors report that 0.25-μm×50-μm discrete devices delivered a power density of 1 W/mm with 2.9-dB gain and 25% efficiency at 60 GHz. A 100-μm monolithic single-stage amplifier demonstrated a record 40% effic... View full abstract»

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  • Ka/Q-band broadband, Ka and W-band low noise HEMT amplifiers

    Publication Year: 1989 , Page(s): 735 - 738 vol.3
    Cited by:  Patents (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (364 KB)  

    The authors describe the design and fabrication of a Ka/ Q-band (27-46-GHz) balanced amplifier, a W-band (81-GHz) low-noise amplifier (LNA), and a Ka-band (28-40-GHz) LNA. These three amplifiers utilize three types of high-electron-mobility-transistor (HEMT) technology. The three technologies are planar-doped/nonplanar-doped AlGaAs and pseudomorphic InGaAs HEMT ... View full abstract»

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  • Trends in military communications

    Publication Year: 1989 , Page(s): 111 - 113 vol.1
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (248 KB)  

    It is noted that the major trend in military command and control systems is toward distributed systems to provide greater survivability against physical and electronic attacks. This also makes possible the sharing of computer resources and data. Distributed architectures involve physical dispersion and functional distribution; that is multiple command and control nodes are dispersed to complicate ... View full abstract»

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  • The HF skywave channel: measured scattering functions for midlatitude and auroral channels and estimates for short-term wideband HF Rake modem performance

    Publication Year: 1989 , Page(s): 830 - 839 vol.3
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (800 KB)  

    Scattering functions for a variety of HF skywave channels, varying from benign or nondisturbed to highly disturbed, have been observed and are presented to illustrate the range of conditions that the communications system designer must contend with. Corresponding short-term performance predictions are presented for a decision-directed wideband Rake modem/codec corresponding to transmission of a 1-... View full abstract»

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  • Performance analysis of meteor burst communication networks

    Publication Year: 1989 , Page(s): 408 - 412 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (344 KB)  

    A Monte Carlo simulation (METEORNET) has been developed to analyze the performance of meteor burst networks. The program employs usable rate and duty cycle statistics derived from the METLINK computer model to predict the waiting time for message reception between nodes in a distributed network. METEORNET is useful in performing trade studies to optimize link performance with respect to the networ... 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
    Save to Project icon | Request Permissions | 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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  • GaAs in the military marketplace

    Publication Year: 1989 , Page(s): 122 - 127 vol.1
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (432 KB)  

    It is noted that, with the advantages (speed and low power) of using GaAs digital integrated circuits, GaAs has now become the technology of choice for high-performance systems. Over the past three years, improvements in processing, manufacturing, and design methodology have been able to overcome the major barriers to the acceptance of this technology, that is yield, cost, stable sources of supply... View full abstract»

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  • Stationarity of wideband HF noise after interference excision

    Publication Year: 1989 , Page(s): 840 - 845 vol.3
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (412 KB)  

    An essential element of HF communications systems is the excision of narrowband interference. The interference in the received signal is excised by first performing a discrete Fourier transform (DFT), then identifying and removing narrowband interferers in the frequency domain, and finally transforming the remaining signal back into the time domain via inverse DFT. In the present work the statisti... View full abstract»

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  • Performance of a coded meteor burst system

    Publication Year: 1989 , Page(s): 413 - 417 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (304 KB)  

    The waiting time performance of a meteor burst (MB) communication system is investigated. The channel model used takes into account the time-varying SNR (signal-to-noise ratio) in an MB system. It is assumed that the message to be transmitted may be divided into several packets and that each packet may contain several code words from an (n, k, e) linear block code. The t... View full abstract»

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  • The performance of a CPFSK trellis code in non-Gaussian noise

    Publication Year: 1989 , Page(s): 769 - 773 vol.3
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (344 KB)  

    Recently R. Padovani and J.K. Wolf (IEEE Trans. Commun., vol.COM-34, no.5 p.446-53, May 1986) extended the Ungerboeck class of trellis codes to signal sets based on combined PSK (phase-shift-keying) and FSK (frequency-shift-keying) modulation (CPFSK). This class of codes has important advantages in the LF and VLF bands, where bandwidth is very scarce and the available transmitter hardware is intol... View full abstract»

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  • Comparison of symbol-rate detector and radiometer intercept receiver performances in a nonstationary environment

    Publication Year: 1989 , Page(s): 359 - 363 vol.2
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (364 KB)  

    The performances of radiometer and DMR (delay and multiply receiver) intercept receivers have been compared. Examples showing the detectability of direct sequence spread spectrum versus spreading ratio and noise fluctuation are given. Comparisons are also made between communicator performance and interceptor performance. It is shown that the DMR can give superior performance in an environment with... View full abstract»

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  • Comparison of detection schemes for fast acquisition direct-sequence spread-spectrum receivers

    Publication Year: 1989 , Page(s): 865 - 869 vol.3
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (340 KB)  

    By using parallel correlation receivers or code-matched filters, the acquisition time of direct-sequence spread-spectrum waveforms can be significantly reduced for any application where a wide code-uncertainty range must be searched. The author discusses parallel acquisition schemes that allow multiple code-phase offsets to be examined at each test. In many applications the presence of data modula... View full abstract»

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  • An optimal receiver using a time-dependent adaptive filter

    Publication Year: 1989 , Page(s): 650 - 656 vol.3
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (512 KB)  

    The optimal time-dependent receiver (OTDR) is presented and shown to be superior to the conventional matched filter receiver when cyclostationary interference is present. This performance advantage is explained by viewing both the OTDR and the conventional matched filter receiver as time-dependent filters that use the spectral correlation properties of the signal. The matched filter is periodic at... View full abstract»

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  • Suboptimum coherent detection of direct-sequence multiple-access signals

    Publication Year: 1989 , Page(s): 128 - 133 vol.1
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (424 KB)  

    The authors consider a class of suboptimum detectors for data transmitted asynchronously by K users employing direct-sequence spread-spectrum multiple access (DS/SSMA) on the additive white Gaussian noise (AWGN) channel. The general structure of these detectors consists of a bank of matched filters, a linear transformation that operates on the matched-filter outputs, and a set of threshol... View full abstract»

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  • Generalized single cycle classifier with applications to SQPSK vs. 2kPSK

    Publication Year: 1989 , Page(s): 754 - 758 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (384 KB)  

    A binary signal classification problem, where the received signal has different spectral correlations for different hypotheses, is investigated. A simple classifier, designated the generalized single-cycle classifier, is developed under additive white Gaussian noise for (1) ideal, (2) unknown phase, and (3) unknown phase and epoch environments. As a specific example, the developed classifier is ap... View full abstract»

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  • Measurement of diversity-combining performance enhancement for fast FH

    Publication Year: 1989 , Page(s): 16 - 19 vol.1
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (292 KB)  

    Repetition of a symbol of L different hops can be used to decrease the error rate of fast frequency hopped (FH) signals. An experimental measurement system that uses a SAW (surface acoustic wave) demodulator and a signal processing microchip is described. The performance of hard-decision majority-vote combining (HDMV) and normalized envelope detection (NED) combining was measured in the p... View full abstract»

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  • Wideband HF noise and interference modeling

    Publication Year: 1989 , Page(s): 846 - 851 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (332 KB)  

    Previously proposed noise and interference models are briefly reviewed, and the limitations of these models are discussed. A simple one-parameter model of noise and interference over wideband HF channels is then presented. An expression for the APD (amplitude probability distribution) of the model is derived. The underlying assumptions of the proposed model are discussed, and a simple model of spe... View full abstract»

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  • The use of linear prediction filters in square law detection of covert signals

    Publication Year: 1989 , Page(s): 289 - 293 vol.1
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (312 KB)  

    The author considers the performance of a square law detector for direct sequence spread spectrum binary phase shift keying (DSSS-BPSK) signals in the presence of broadband interference when filtering is employed to excise the interference. A linear predictive filter operating at steady state is considered as the excision filter. It is demonstrated that large gains can be achieved by the use of pr... 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)
    Save to Project icon | Request Permissions | 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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  • Packet recovery and error correction in high-speed wide-area networks

    Publication Year: 1989 , Page(s): 551 - 557 vol.2
    Cited by:  Papers (10)  |  Patents (32)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (540 KB)  

    The author presents a novel technique for reducing packet loss rate in high-speed wide-area networks in which the BER (bit-error rate) is low. Grouping packets into blocks and adding a packet that computes parity over bits of all packets in a block allow a data recipient to reconstruct any single packet in a block, using the other packets and the block parity packet. The missing packet is identifi... View full abstract»

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  • Adaptive HF for voice and data

    Publication Year: 1989
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (32 KB)  

    Summary form only given. The authors describe an adaptive HF system for voice and video. The system uses information obtained from a link quality analysis and/or ionospheric soundings to determine the appropriate link and frequency over which to communicate. In addition, the system can be frequency hopped, thereby reducing the probability of being jammed. The improved performance obtained using fr... View full abstract»

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  • Energy detector performance in a noise fluctuating channel

    Publication Year: 1989 , Page(s): 85 - 89 vol.1
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (348 KB)  

    The authors address the energy detection performance of a detector, or more specifically, the determination of the required signal-to-noise ratio (Ps/Pn) for given probabilities of detection (Pd) and probabilities of false-alarm (Pfa) in a noise fluctuating channel. A theoretical model for evaluating energy detection p... View full abstract»

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  • Automatic modulation recognition of digitally modulated signals

    Publication Year: 1989 , Page(s): 645 - 649 vol.3
    Cited by:  Papers (29)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (364 KB)  

    A modulation recognizer that automatically reports modulation types of constant-envelope modulated signals is developed using zero-crossing techniques. The zero-crossing sampler, as a signal conditioner, has the advantage of providing accurate phase transition information over a wide dynamic frequency range. Signal parameters, such as zero-crossing variance, carrier-to-noise ratio (CNR), and carri... View full abstract»

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  • High efficiency autotrack feed

    Publication Year: 1989 , Page(s): 316 - 320 vol.1
    Save to Project icon | Request Permissions | 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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