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Military Electronics, IEEE Transactions on

Issue 3 • Date July 1965

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Displaying Results 1 - 24 of 24
  • [Front cover]

    Publication Year: 1965 , Page(s): c1
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  • IEEE Military Electronics Group

    Publication Year: 1965 , Page(s): c2
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  • Table of contents

    Publication Year: 1965 , Page(s): nil1
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  • Editorial

    Publication Year: 1965 , Page(s): 188
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  • Delay Line Secondaries in Phase-Modulated Sweep Integrators

    Publication Year: 1965 , Page(s): 189 - 196
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    A video sweep integrator is a device for adding successive radar returns of transmitted pulses. One type of sweep integrator uses an ultrasonic delay line for storage, requiring that the delay line transmission be in the form of a modulated carrier. Addition is obtained by means of a closed regenerative loop that operates for a finite time to provide uniformly weighted addition or operates continuously with exponentially decaying memory. The former type of operation is called iteration to distinguish it from the continuous operation called integration. This paper treats the case of phase modulation imposed upon the carrier. Delay line secondary, or spurious, responses result from multipath propagation through the delay line. The cumulative effect of these secondaries after circulation in the sweep integrator or iterator may set a severe limitation on dynamic range. This paper treats two cases of secondary buildup: 1) the coherent buildup case in which relative buildup of secondaries is much greater than that of the signal, and 2) noncoherent buildup in which the built-up secondary effect is less than in the coherent case. It is suggested that it is possible to assure noncoherent secondary buildup by changing the carrier frequency in an irregular manner upon each circulation around the regenerative loop. View full abstract»

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  • Optimum and Suboptimum Detection of Directional Gaussian Signals in an Isotropic Gaussian Noise Field Part I: Likelihood Ratio and Power Detectors

    Publication Year: 1965 , Page(s): 197 - 208
    Cited by:  Papers (6)
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    The detection of underwater signals is frequently accomplished by highly directional hydrophone arrays. This paper reviews some of the well-known optimum techniques that are used in processing signals of this type, and compares them to simpler suboptimum methods. It appears that the main effect of optimum detectors is to eliminate the low frequencies where there is substantial correlation between the noise components received by adjacent hydrophones. This effect is easily approximated by simple suboptimum receivers. The question of the detection of modulated noise signals is also considered, but it is concluded that if the background noise level is known precisely, knowledge of the modulation waveshape does not contribute very much to detectability. View full abstract»

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  • Part II: Degradation of Detectability Due to Clipping

    Publication Year: 1965 , Page(s): 208 - 211
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (733 KB)  

    The output signals from the hydrophones in a directional sonar array are frequently clipped before being processed further. The effect of this is analyzed in this paper by comparing the figures of merit of likelihood-ratio detectors operating on clipped and unclipped data. It is found that if the number of hydrophones is large, the figure of merit is reduced by a factor of about 2/¿ from the optimum value. View full abstract»

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  • Optimum Signal Design and Processing for Reverberation-Limited Environments

    Publication Year: 1965 , Page(s): 212 - 229
    Cited by:  Papers (39)  |  Patents (1)
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    In this paper we discuss the problem of designing optimum signals and receivers for an active sonar system operating in an environment in which the principal cause of interference is reverberation. We have considered only the problem of target detection (as opposed to the problem of range or Doppler estimation). View full abstract»

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  • Spatial Ambiguity and Resolution for Array Antenna Systems

    Publication Year: 1965 , Page(s): 229 - 237
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1684 KB)  

    The signal ambiguity function is derived and analyzed for radar (sonar) systems employing array antennas. It is shown that angle resolution is essentially independent of range-Doppler resolution in the main antenna beam and that the antenna directivity function can have a strong effect on waveform design. It is also shown that angle ambiguity is appreciably influenced by signal bandwidth; in particular, signal bandwidth can be traded for a reduction in angle ambiguity in an array whose element spacing is greater than one-half wavelength. View full abstract»

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  • Statistical Description of Nonlinear Signal Processing in Array Antenna Systems

    Publication Year: 1965 , Page(s): 237 - 246
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    A statistical analysis is made of a superlimited phased array when a sinusoid and Gaussian noise are independently introduced into the element-channel antenna elements. A mathematical expression is derived for the probability-density function of the beam-channel envelope in tenns of element-channel signal-to-noise power ratio and angular position of target from main beam. This density function is used to study the envelope detection capabilities of a superlimited phased-array system. A comparison study of the detection capabilities of the superlimited phased array and a linear system points out the "sidelobe suppression effect" and the "noise quieting effect" exhibited by the nonlinear system. Experimental results obtained with a 60-element array antenna system with noninear signal processing are reported and compared with theory. View full abstract»

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  • Automatic Correction of Timing Errors in Magnetic Tape Recorders

    Publication Year: 1965 , Page(s): 246 - 254
    Cited by:  Papers (7)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6128 KB)  

    A basic problem in magnetic recording is the preservation of accurate time relationships between reproduced bits of information. If information is recorded at a given rate, the reproduced signal rate will tend to deviate from this rate. Servo systems for controlling the mechanisms of the machine can maintain the reproduced signal rate equal to the recorded signal rate, averaged over a period of a few milliseconds. Mechanical servos cannot, however, prevent short-term deviations in reproduced signal rate, because of their relatively slow response. Electronically variable delay lines (EVDLs) have been developed which, because of their relatively fast response, can further reduce timing errors. This paper presents a mathematical analysis of the problem and of the requirements imposed on the EVDLs. Two devices for the accomplishment of electronically variable delay are then described, one for high-frequency signals, and one for low-frequency signals. Experimental results obtained by using these two delay lines are also presented. View full abstract»

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  • Radar System Performance Charts

    Publication Year: 1965 , Page(s): 255 - 263
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    The fundamental limits to radar performance in search and tracking can be expressed on three charts, in terms of products involving transmitted power, antenna gain, and effective aperture area. Locations of past and present radar systems on these charts disclose evolutionary trends in system design and indicate regions of practical and economic balance between transmitter and antenna complexity, in terms of ratios of power to gain and aperture. The basis of choice for operating frequency is clarified for different applications of radar, such as air surveillance, precision tracking, weapon control, and combinations of these tasks. It is suggested that these historical trends, derived from a large sample of successful radar systems, will furnish a better guide to economic optimization than will empirical cost equations. They are also helpful in comparing diverse approaches to radar system design, and in estimating the dependence of proposed systems upon new component and technique developments. The examples used in this paper are drawn primarily from ground-based radar systems, and serve to clarify the relationships between conventional and phased-array radar systems used for aircraft and missile detection, tracking, and weapon control. View full abstract»

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  • An Optimum Design of Ambiguity Function, Antenna Pattern, and Signal for Side-Looking Radars

    Publication Year: 1965 , Page(s): 264 - 278
    Cited by:  Papers (14)
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    The design of antenna pattern and transmitted signal for a coherent-side-looking (range-azimuth) synthetic antenna radar is studied. The general design criterion is to minimize all spurious responses in the ambiguity function under the restraints of finite antenna aperture and signal bandwidth. The problem is completely solved for any set of consistent constraints. The interplay between aperture size, range and azimuth resolution, and spurious response level for the optimum design is exhibited, and antenna aperture illuminations, signal amplitude and phase modulation, and pulse repetition frequency are specified. View full abstract»

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  • A Two-Step Sequential Procedure for Improving the Cumulative Probability of Detection in Radars

    Publication Year: 1965 , Page(s): 278 - 287
    Cited by:  Papers (3)
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    Sequential detection procedures, which may be used with phased-array radars, can provide a significant improvement in search capability as compared to uniform scanning. This paper discusses the improvement in cumulative detection probability (the probability that an approaching target is detected before it reaches a given range) which can be obtained with the two-step sequential test, first described by Finn [6]. In this test, a first pulse is transmitted in each beam position. If a threshold crossing is observed in any range cell, a second pulse of higher energy is transmitted and the returns compared with a higher threshold. A target is declared present if and only if threshold crossings are observed on both pulses in the same range cell. Curves of cumnulative detection probability vs. range are given for a nonfluctuating target and for two of the target fluctuation models considered by Swerling [7]. Results are given for three values of range resolution, and the radar parameters that optimize performance are tabulated in each case. In practical cases where the range resolution is from one to ten percent of the range, the sequential test considered here yields an energy saving of 3 to 4 dB as compared with uniform scanning. View full abstract»

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  • Activated Delay-Line Receiving Arrays

    Publication Year: 1965 , Page(s): 287 - 293
    Cited by:  Patents (1)
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    A discussion of the theory and applications of activated delay lines is presented. The term "activated delay line" is derived from the fact that the equivalent circuit of a ceramic electroacoustic receiving transducer is a capacitor in series with a voltage generator and for this reason may be inserted directly into an LC delay-line receiving array matrix. Equations are derived which give array gain as a function of the number of serially added array elements. Very large arrays are theoretically possible. Since activated delay lines are composed entirely of passive components, they are very rugged, reliable, and relatively inexpensive. View full abstract»

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  • Monopulse Radar Tracking Techniques

    Publication Year: 1965 , Page(s): 293 - 294
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  • Ground Clutter Calculation for Airborne Doppler Radars

    Publication Year: 1965 , Page(s): 294 - 297
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  • The Effect of Phase Errors on Weighted Spectra

    Publication Year: 1965 , Page(s): 298 - 299
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  • An Alternate Derivation on Phase Errors

    Publication Year: 1965 , Page(s): 299
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  • Contributors

    Publication Year: 1965 , Page(s): 300 - 302
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  • Call for Papers 1966 Aerospace Conference

    Publication Year: 1965 , Page(s): 303
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  • Index to IEEE Transactions on Military Electronics Volume MIL-9, 1965

    Publication Year: 1965 , Page(s): 1 - 4
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  • Radio Spectrum Utilizationtilization

    Publication Year: 1965 , Page(s): 4-a
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  • Information for authors

    Publication Year: 1965 , Page(s): 4b
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Aims & Scope

This Transactions ceased publication in 1965. The new retitled publication is IEEE Transactions on Aerospace and Electronic Systems.

Full Aims & Scope