| Time-Frequency, Bi-Frequency Detection Analysis of Noise Technology Radar |
SEP 2006 |
124 pages |
| Authors:
Eugene R. Heuschel; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | Enemy integrated air defense systems (IADS) using low probability of intercept (LPI) emitters can cause significant problems for suppression of enemy air defense (SEAD) techniques. New threat emitter configurations using low-power random noise modulation have a significant processing gain unavailable to non-cooperative intercept receivers. Consequently, the detection of these emitters can not be accomplished with conventional intercept receiver detection methods. This thesis examines the use of time-frequency, bi-frequency signal detection ... |
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| Optimal Subband Coding of Cyclostationary Signals |
29 SEP 2003 |
156 pages |
| Authors:
Soura Dasgupta; IOWA UNIV IOWA CITY
|
| The purpose of the award was to study the subband coding of cyclostationary signals. We have completely solved the problem of subband coding with uniform filter banks. We have also shown that our approach applies also to optimization of Discrete Multitone Transmission Systems. In the coming year we shall address the issue of nonuniform filter banks. |
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| Localization of Wireless Emitters Based on the Time Difference of Arrival (TDOA) and Wavelet Denoising |
MAY 1999 |
67 pages |
| Authors:
Ralph D. Hippenstiel; Tri T. Ha; Unal Aktas; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The localization of mobile wireless communication units using time difference of arrival (TDOA) is studied. The wavelet transform is used to increase the accuracy of TDOA estimation. Several denoising techniques based on the wavelet transform are presented. These techniques are applied to different types of test signals and to a simulated baseband GSM signal. The results of the denoising techniques are compared to the ones employing no denoising in terms ... |
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| Getting Started Guide for the Small Arms Range Noise Assessment Model (SARNAM) |
MAY 1999 |
21 pages |
| Authors:
Larry Pater; Pamela Woof; Diane Rhoads; Mike White; CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
|
| Realistic training for soldiers includes firing weapons at small armsranges on military installations. Noise from these ranges can annoy people living in the surrounding area. In an effort to preserve this critical training,installations having ranges must conduct an evaluation of community noise exposure and develop a plan to minimize annoyance to local residents. The Small Arms Range Noise Assessment Model (SARNAM) is a software program that allows range managers to ... |
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| Conversion of Laser Phase Noise to Amplitude Noise in a Resonant Atomic Vapor: The Role of Laser Linewidth |
15 APR 1999 |
12 pages |
| Authors:
James C. Camparo; John G. Coffer; AEROSPACE CORP EL SEGUNDO CA ENGINEERING AND TECHNOLOGY GROUP
|
| When laser light propagates through a resonant medium, the transmitted beam can exhibit excess intensity noise AMPLITUDE MODULATION (AM). In a semiclassical description of the phenomenon, laser phase noise (PM) induces fluctuations in the medium's electric susceptibility, which in turn cause fluctuations in the transmitted intensity. The process provides an efficient means for PM-to-AM conversion, and intuition suggests that large linewidth lasers should exhibit much greater PM-to-AM conversion than narrow ... |
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| Development of a Muffler for Small Arms Range Noise Mitigation |
SEP 1998 |
51 pages |
| Authors:
Larry Pater; Anthony Krempin; CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
|
| Small arms fire can result in noise complaints from nearby residents. The objective of the project reported herein was to provide a mitigation strategy to reduce small arms noise impact in the neighborhood of Camp Dodge, IA. The selected strategy was a low cost muzzle blast muffler. The U.S. Army Construction Engineering Research Laboratories (USACERL) designed, constructed, and tested several variations of mufflers. The basic design consists of a tube ... |
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| Modeling and Control in Distributed Parameter Physical Systems |
15 MAY 1998 |
15 pages |
| Authors:
H. T. Banks; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
|
| Research efforts and achievements in the area of modeling and control in distributed parameter physical systems are summarized. Progress is reported on specific topics including: (1) control of structure borne noise/mechanical vibrations, (2) modeling of hepatic uptake and elimination of dioxin, (3) modeling and parameter estimation in electromagnetic field/solid interactions, and (4) vibration based damage detection and health monitoring. |
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| Vibrational Motion of Arctic Pack Ice |
25 SEP 97 |
16 pages |
| Authors:
John Dugan; William Morris; Zandy Williams; ARETE ASSOCIATES ARLINGTON VA
|
| There are many physical mechanisms responsible for vibrations of sea, and they force motions in a very wide band of frequencies from less than 0.01 Hz to greater than 100 Hz. Detailed measurements of the vertical velocity in this frequency band were previously shown to be produced by gravity waves, ridging events and wind turbulence. In this paper, higher frequency motions as measured by geophones for frequencies up to about ... |
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| Semiconductor Laser Low Frequency Noise Characterization |
DEC 96 |
108 pages |
| Authors:
Lute Maleki; Ronald T. Logan; JET PROPULSION LAB PASADENA CA TIME AND FREQUENCY SYSTEMS RESEARCH GROUP
|
| This work summarizes the efforts in identifying the fundamental noise limit in semiconductor optical sources (lasers) to determine the source of 1/F noise and it's associated behavior. In addition, the study also addresses the effects of this 1/F noise on RF phased arrays. The study showed that the 1/F noise in semiconductor lasers has an ultimate physical limit based upon similar factors to fundamental noise generated in other semiconductor and ... |
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| Coherent Phase Wide Band Demodulation Technique for Turbomachinery Cavitation Detection and Monitoring |
APR 1996 |
13 pages |
| Authors:
Jen Jong; Tom Nesman; Wayne Bordelon; Jess Jones; Tom Zoladz; AI SIGNAL RESEARCH INC HUNTSVILLE AL
|
| This paper discusses a Coherent Phase Wide Band Demodulation (CPWBD) technique for turbopump cavitation detection and monitoring. The principle of cavitation detection is based on the unique nonlinear modulation phenomenon associated with pump cavitation in which the periodic shaft rotational motion (and/or its harmonic motion) amplitude modulates the wideband noise generated from the collapse of cavitation bubbles. However, these periodicities associated with shaft rotation are hidden during the physical wide ... |
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| Richmond Harbor, Contra Costa County, CA.; Navigation Improvement Project General Design Memorandum |
JAN 96 |
540 pages |
| Authors:
CORPS OF ENGINEERS SAN FRANCISCO CA SAN FRANCISCO DISTRICT
|
| The Richmond Harbor Navigation Improvement Project located in Richmond, California, will create a safe navigation channel of sufficient depth for modern bulk carriers scheduled to use the Port's terminal facilities. The project area includes a channel extending from the Long Wharf Maneuvering Area through the Richmond Entrance Channel, the Potreto Reach and Sharp Turn with a turning basin at Point Potreto, the Inner Harbor, and the Santa Fe Channel. Furthermore, ... |
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| Reduction of 40-mm Muzzle Blast and Flash for AC-130 Gunship |
OCT 94 |
25 pages |
| Authors:
Kevin S. Fansler; Raymond Von Wahlde; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Muzzle devices for reducing the blast and flash levels received by the AC-130 gunship were investigated. A noise suppressor design decreased the blast levels only minimally while the flash level increased compared to the standard flash hider. Extension tubes with 6-inch and 8-inch exit diameters were also tried with no better results. A flash hider with an 8-inch exit diameter brought the flash levels down to new lows but the ... |
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| Literature Review of the 'Errors-In-Variables' Approach to the Problem of System Identification |
JUL 93 |
14 pages |
| Authors:
Betty Emslie; AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA)
|
| The papers reviewed here deal with various aspects of the problem of system identification when all the observed variables are contaminated by noise errors. Theoretical issues of identifiability and practical methods for developing algorithms to estimate parameters of a dynamic system are considered. The total least squares approach and the Koopmans-Levin method are among the methods discussed. Both these methods are strongly based on matrix singular value decomposition, which is ... |
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| Dynamic Mechanical Materials Characterization and Analysis Using a Dynamic Mechanical Thermal Analyzer |
JAN 91 |
26 pages |
| Authors:
Walter M. Madigosky; NAVAL SURFACE WARFARE CENTER SILVER SPRING MD
|
| Material characterization is essential both for design use and control. Specifically, materials designed for vibration damping and noise suppression precise values of the modulus and loss factor over a wide range of frequency and temperature. Until now, apparatus for making such measurements had very limited frequency and temperature ranges, were of questionable accuracy, and were usually very time consuming to operate. This report presents data as a function of temperature, ... |
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| Sound Localization by Human Observers Symposium Proceedings Held in National Academy of Sciences on 14-16 October 1988 |
01 JUL 89 |
68 pages |
| Authors:
NATIONAL RESEARCH COUNCIL WASHINGTON DC
|
| The relation between binaural perception of actual sounds in space and of stimuli presented over headphones, base on head-related transfer functions, showed a high correlation. Listeners reported that the sound image presented over headphones remained internal to the head and not external in space, as with natural sound. Head movement, context, bias, experience, and integration of information across senses remain probable contributions to externalizing headphone-delivered sounds at their real-world positions. ... |
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| Sound Enhancement and Modulation of Self-Resonating Cavitating Jets for Underwater Noise Generation |
JUL 85 |
|
| Authors:
Georges L. Chahine; Virgil E. Johnson Jr.; Gary S. Frederick; Ron E. Watson; TRACOR HYDRONAUTICS INC LAUREL MD
|
 | The natural tendency of an axisymmetric submerged jet to form large scale structures in its shear layer is enhanced using acoustic oscillators and hydroacoustic oscillations. Organ pipe tube lengths are tuned to the jet natural oscillation frequency to form very effective noise generators. The principle of operation of this generator, STRATOJET (TM), is described in this report, and the influence of the various parameters: tube length, nozzle diameter, pressure drop ... |
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| HF (High-Frequency) Channel Probe |
31 MAY 85 |
|
| Authors:
Roy P. Basler; Philip B. Bentley; Gary H. Price; Charles L. Rino; Denise K. Rust; SRI INTERNATIONAL MENLO PARK CA
|
| An experiment in Greenland has measured the transfer characteristics for HF signals propagation through disturbed regions of the ionosphere. Transmissions over the 1-hop path from Narssarssuaq to Thule have suffered distortions in the range (propagation time) and Doppler domains on the order of hundreds of microseconds and tems of Hertz, respectively. A frequency-modulated continuous wave (FMCW) waveform was used for oblique sounding purposes, and a pseudorandom noise modulation with a ... |
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| Multilevel Mate Pair Code Compressor for Codes Expanded by the Process of Butting. |
14 NOV 1983 |
|
| Authors:
F. S. Gutleber; DEPARTMENT OF THE ARMY WASHINGTON DC
|
| Multilevel code mates A and B expanded in accordance with the expressions A = a, b sub K and B = a sub K, b are compressed to a lobeless basic mate pair by repeatedly compressing corresponding code mate pairs in successive stages to provide diminishing codes of half the code length by amplifying the code mates by a predetermined amplification factor and then adding and subtracting the code mates ... |
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| Analysis of Legal Precedents and Land-Use Controls as applied to the Installation Compatible Use Zone (ICUZ) Program |
JAN 1983 |
|
| Authors:
Lynn Anne Engelman; Richard Raspet; CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
|
| This report describes a study conducted by the U.S. Army Construction Engineering Research Laboratory (CERL) into the legal precedents and land-use controls applicable to the Army's Installation Compatible Use Zone (ICUZ) program. The ICUZ program is designed to protect an installation's mission as well as the public by identifying heavily noise-impacted areas so local governments and the installation can use local land-use planning to minimize noise-sensitive development in areas impacted ... |
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| Design of the STIFT Time and Frequency Transfer Microwave Ground Terminal |
Dec-1982 |
21 pages |
| Authors:
R F Vessot; H Penfield; E Imbier; HARVARD COLL OBSERVATORY CAMBRIDGE MA CENTER FOR ASTROPHYSICS
|
| The Satellite Time and Frequency Transfer System (STIFT) is intended to provide, simultaneously, global time comparisons at the subnanosecond level and frequency comparisons to better than 1 part in 10(14). It utilizes an orbiting hydrogen maser clock and frequency standard that communicates, via microwave links, time and frequency information to earth terminals operated by hydrogen masers controlling local clocks. A two-way microwave link, to and from the space vehicle provides ... |
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| Detection of a Dual Channel Differential Phase Modulated Signal in Correlated Noise |
08 JUN 1982 |
|
| Authors:
Clifton C. Merchant; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
|
| The signal detection characteristics of a two input channel receiver is studied. The signals received on both channels are random Gaussian, narrowband processes identical except for a known channel-to-channel time delay. For narrowband representation, the time delay is treated as a differential phase modulation of the two signals. The noises on each of the two receiver channels are also random Gaussian, processes which are jointly wide sense stationary and correlated. ... |
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| Design and Operation of a Simple Circuit Useful as a Modulator to Generate Arbitrary Composite ASK and PSK Carriers |
JUN 1982 |
|
| Authors:
Allan M. Maughan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In radio transmission of binary data, it is often desirable to conserve bandwidth at the expense of signal power. To reduce carrier bandwidth (switching rate), M bits are used to change a parameter of the carrier, so the carrier has 2M discrete combinations of amplitude, frequency, or phase. |
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| Intercept Vulnerability of Direct Sequence Pseudo-Noise Encoded Spread Spectrum Waveforms. |
15 DEC 1979 |
|
| Authors:
Thomas J. Hall; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| Direct sequence pseudo-noise (PN) encoded spread spectrum (SS) waveforms are examined for their vulnerability to intercept and message reconstruction without knowledge of the PN code used. Two generic modulation formats are described and an intercept receiver model is proposed. Receiver outputs are calculated and it is shown that message reconstruction is possible for both generic modulation formats under appropriate conditions. (Author) |
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| Ionospheric Measurements from Navstar Satellites |
DEC 1978 |
47 pages |
| Authors:
P. S. Jorgensen; GOVERNMENT-INDUSTRY DATA EXCHANGE PROGRAM
|
| For several months, three Navstar satellites have been extensively tracked by monitor stations located in California, Alaska, Hawaii, and Guam. As part of this tracking process, data was acquired which s a measure of the ionospheric delay encountered by the navigation signal from the satellites. This report describes the measurement techniques used at the monitor stations, the data obtained from these measurements, and the methods used to compute ionospheric delay. ... |
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| Classification of Amplitude-Modulated Noise Patterns with Extended Practice. |
DEC 1978 |
|
| Authors:
James H. Howard Jr.; James A. Ballas; CATHOLIC UNIV OF AMERICA WASHINGTON D C HUMAN PERFORMANCE LAB
|
| Four listeners were given extended practice in an eight-category classification task (3072 trials). The stimuli were sixteen amplitude-modulated noise patterns that varied in modulation frequency (Tempo) and attack (Quality). Two listeners learned an eight-category partition that was based primarily on stimulus Quality, and two learned a partition that was based primarily on stimulus Tempo. The resulting confusion data were analyzed in terms of the aural classification model proposed by Howard, ... |
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| Inductive Communication System. |
26 SEP 1978 |
|
| Authors:
Wallis L. Teeter ; David J. Richter; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An apparatus providing multiple conversations over limited range. Pseudo-noise modulations and specific address coding permit multiple conversations between a base station and several vehicles or between the vehicles. A variable power source gives even greater range control for private communication. By utilizing portable communicators, vehicles can be guided by individuals around the base station. (Author) |
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| Flexural Vibrations of Conical Shells with Free Edges |
MAR 66 |
28 pages |
| Authors:
W. C. Hu; J. F. Gormley; U. S. Lindholm; SOUTHWEST RESEARCH INST SAN ANTONIO TX
|
| Experimental data is presented for the resonant frequencies and associated mode shapes of truncated conical shells with free edges in transverse vibration. A wide range of the geometrical and modal parameters is covered. A semi-empirical frequency equation is developed which can be used to predict the first axial mode resonances with satisfactory accuracy. |
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Reports by Keyword(s)
NOISE MODULATION
