| FORTRAN Subroutines for Zero-Phase Digital Frequency Filters |
MAR 86 |
|
| Authors:
Donald G. Albert; COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
|
 | This report describes and gives user instructions for a series of FORTRAN subroutines that can be used to design and apply zero-phase freqeuncy filters to digitized data. The general properties of these filters are discussed and complete listings are presented. Keywords include: Bandpass filters; Bandstop filters; Digital filters; FORTRAN; High pass filters; and Low pass filters. |
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| Adaptive Canceller Limitations due to Frequency Mismatch Errors |
02 JAN 86 |
|
| Authors:
Karl R. Gerlach; NAVAL RESEARCH LAB WASHINGTON DC
|
| The effects of frequency mismatch errors on adaptive cancellers are investigated. Frequency mismatch errors occur because of errors in the synthesis process of the bandpass filters designed to be identical which are in each input channel. These frequency mismatches among the channels result in cancellation degradation. Tapped delay line transversal filters can be used to compensate for these frequency mismatches and thus improve cancellation performance. A pole/ zero error model ... |
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| Research on Devices for Integrated Millimeter Wave Systems |
OCT 85 |
|
| Authors:
S. E. Schwarz; CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB
|
| Planar technology for millimeter wave circuits has been studied. Coplanar waveguide filters have been developed. A fully planar monolithic 35-GHz oscillator and a planar 70-GHz receiver have been built. Keywords: millimeter- wave intergrated circuits; gallium arsenide devices; gunn diodes; planar circuits. Contents: Antennas and Waveguides for Far-Infrared Integrated Circuits; Planar Multi-Mode Detector Arrays for Infrared and Millimeter-Wave Applications; Monolithic Integration of a Dielectric Millimeter-Wave Antenna and Mixer Diode: An Embroyonic ... |
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| Detection, Estimation, and Multidimensional Processing of Single Evoked Potentials |
SEP 85 |
|
| Authors:
J. I. Aunon; C. D. McGillem; PURDUE UNIV LAFAYETTE IN EEG SIGNAL PROCESSING LAB
|
| A new method of generating and selecting features for computer classification of ERP waveforms is described. The technique employs features that are time samples of measured ERP waveforms that have been bandpass filtered. An improvement of more conventional techniques is shown with both simulated and measured data. A comparison of performance of a quadratic classifier with optimum feature selection is made with one using (suboptimal) forward segmented feature selection. Details ... |
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| Bandpass Spatial Filtering and Information Content |
JUL 85 |
50 pages |
| Authors:
Gilbert G. Kuperman; HARRY G ARMSTRONG AEROSPACE MEDICAL RESEARCH LAB WRIGHT- PATTERSON AFB OH
|
 | Gaussian weighted, bandpass spatial filters were applied to pictures of tactical fighter aircraft through two dimensional, Fourier Transform processing. Subjects were required to rate image interpretability and report their confidence. No significant difference was found between aircraft for interpretability or confidence. Filter center frequency was found to be highly significant (p < 0.01), and the difference between subjects was found to be significant (p < 0.05) with respect to interpretability. ... |
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| ELINT Sensor Parameterization and Definition |
19 JUN 85 |
|
| Authors:
Bill Buckles; JET PROPULSION LAB PASADENA CA
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| This memo describes the modeling of the superheterodyne radar receiver and defines the parameters of interest. The modeling details are included. Both a flow chart and source code (FORTRAN) for the model are included. The report ends with documentation of the model testing and validation. |
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| A Linear Array for Rayleigh Scattering |
11 JUN 85 |
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| Authors:
L. Talbot; CALIFORNIA UNIV BERKELEY DEPT OF MECHANICAL ENGINEERING
|
| Gas density under combustion conditions can be obtained by measuring the intensity of the molecular (Rayleigh) scattering of light from a laser beam. A system which obtains an essentially continuous record of the density along a length of the laser beam is described. The temperature and degree of combustion can thus be determined for a number of interesting combustion configurations, which will ultimately lead to a better description and understanding ... |
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| A Matched Filter Algorithm for Acoustic Signal Detection |
JUN 85 |
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| Authors:
D. W. Jordan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| This thesis is a presentation of several alternative acoustic filter designs which allow Space Shuttle payload experiment initiation prior to launch. This initiation is accomplished independently of any spacecraft services by means of a matched band-pass filter tuned to the acoustic signal characteristic of the Auxiliary Power Unit (APU) which is brought up to operating RPM's approximately five minutes prior to launch. These alternative designs include an analog filter built ... |
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| Microwave SAW (Surface Acoustic Wave) Monochromator. |
24 MAY 1985 |
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| Authors:
A. Ballato; DEPARTMENT OF THE ARMY WASHINGTON DC
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| An acoustic surface wave device is configured as a bandpass filter. The device has similar groups of sinusoidal corrugations cut into portions of both the top and bottom surfaces of an otherwise flat piezoelectric substrate. A pair of input interdigital transducers is located upon one end of the top flat surface of the substrate. A similar pair of output interdigital transducers is located on the bottom flat surface of the ... |
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| A Real Time Index of Geomagnetic Background Noise for the M.A.D. (Magnetic Anomaly Detection) Frequency Band |
FEB 85 |
44 pages |
| Authors:
A. Bernardi; A. C. Fraser-Smith; O. G. Villard; STANFORD UNIV CA SPACE TELECOMMUNICATIONS AND RADIOSCIENCE LAB
|
| An index of geomagnetic activity in the upper part of the ultra low frequency (ULF) range (less than 4.55 Hz) has been developed. This index will be referred to as the MA index (magnetic activity index). The MA index is prepared every half hour and is a measure of the strength of the geomagnetic activity in the Pcl-Pc3 pulsation frequency range during that half hour period. Activity in the individual ... |
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| A Standard Aircraft Diffusion Flame: Spectral Characteristics and a Feasibility Study for Developing an Alternate Calibration Source for Aircraft Optical Fire Detection Systems |
30 DEC 84 |
|
| Authors:
R. L. Hawkins; K. N. Rao; OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS
|
| The standard aircraft diffusion flame source presents practical difficulties due to its lack of controllability and its production of large amounts of smoke and soot. A source which is more convenient to handle, but which emulates the spectral and power characteristics of the standard flame, might prove useful. The requirements of such a flame were evaluated by measuring the spectral and power characteristics of a standard aircraft diffusion flame over ... |
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| Detection of Angular Modulated Electromagnetic Signals. |
25 DEC 1984 |
|
| Authors:
P. Van Etten; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| A signal processing circuit which operates on a spread spectrum received signal to compress it into a waveform of sufficient amplitude to allow detection by conventional means. The received signal is filtered and split onto two paths, each path being mixed with an upper or lower single sideband created by an oscillator and modulator combination. The output of each mixer is filtered and mixed together in a third mixer, the ... |
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| Margin Leveling Algorithm for Fully Saturated Satellite Transponder with CDMA (Code Division Multiple Access) Signalling |
DEC 84 |
|
| Authors:
E. J. Putt; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| For satellite communications in a noninterfering environment, a specific downlink carrier-to-noise ratio (CNR) is needed to achieve a desired bit error rate. In an interfering environment, and additional CNR or margin is needed to overcome interfering effects. A situation may arise where the desired margins cannot be achieved due to limited uplink and satellite transmit power. If this is the case, margin leveling should occur in order to decrease the ... |
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| A Short Range, High Accuracy Radar Ranging System |
DEC 84 |
|
| Authors:
K. E. Thomsen; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| This paper described the design and test of a low power, highly accurate FM-CW radar ranging system. The objective of the design wad to provide an inexpensive aircraft-to-aircraft ranging system with + or - 1 foot accuracy at ranges up to 400 feet. Particular detail is given to describing the design and test frequency tracking circuit. Quartz crystals were used to make the narrow bandpass filters necessary for good frequency ... |
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| A Simplified GPS C/A Receiver Front End With Low Noise Performance |
Nov-1984 |
9 pages |
| Authors:
D D Davis; A D Clements; NATIONAL BUREAU OF STANDARDS BOULDER CO
|
| A redesign of the antenna electronics package for the NBS/GPS C/A receiver has resulted in significantly reduced cost and improved performance. Major improvements include a simplified and more reliable multiplier/mixer, elimination of all twelve piston trimmer tuning capacitors in the original design, elimination of expensive bandpass filters, less expensive antenna and a simplified packaging scheme. |
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| Adaptive Spread Spectrum Receiver Using Acoustic Surface Wave Technology |
31 MAY 1984 |
|
| Authors:
P. Das; L. B. Milstein; RENSSELAER POLYTECHNIC INST TROY NY DEPT OF ELECTRICAL COMPUTER AND SYSTEMS ENGINEERING
|
| This technical report summarizes the results of the research we have been engaged in regarding the use of surface acoustic wave devices in direct sequence spread spectrum receivers. The heart of this research has been the use of the device as a real-time Fourier transformer. A system of this type is sometimes referred to as a compressive receiver, and our use of the system has been primarily as a means ... |
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| Varying Bandpass of Optical Spatial Filter by Rotating Mirrors Having Changing Reflectivity. |
15 MAY 1984 |
|
| Authors:
D. W. Evans; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| In a system of real-time coherent optical filtering of visual imagery having a Fabry-Perot interferometer for use as a variable bandpass spatial filter, the improvement relates to the pair of mirrors of the interferometer mounted in spaced parallel relationship to one another for rotation about a common axis. The mirrors each have a reflectivity value which changes as a function of rotation. Thus, the bandwidth of the interferometer in acting ... |
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| Electroding of Multi-Layered Epitaxial Structures. |
15 MAY 1984 |
|
| Authors:
G. D. Robertson Jr; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| To locate the very thin transparent low-resistivity planar electrode layers in a multilayer epitaxial structure for an electrooptic tunable filter, one edge of the stack is covered with a dielectric, and a long diagonal strip opening is made through the dielectric. A common metal electrode is formed on the opposite edge of the stack. The edge with the strip opening is immersed in a plating solution and potential applied at ... |
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| System for Detection of Transducer Defects. |
01 MAY 1984 |
|
| Authors:
Mark B. Moffett; William L. Konrad; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| Apparatus and method for nondestructive detection of loose parts or faulty bonds in sound transducers by measuring erratic second-order nonlinear difference-frequency responses of the test transducer to a pulsed high level dual-frequency sound field produced by a high power projector. Such field may be generated by combining a high frequency carrier signal at frequency fo with a low frequency tone burst signal at frequency f/2 in a double balanced modulator ... |
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| Millimeter Wave Suspended Substrate Multiplexer. |
21 FEB 1984 |
|
| Authors:
A. R. Hislop; D. Rubin; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A millimeter wave suspended substrate multiplexer is disclosed which is comprised of a plurality of hybrid-filter-hybrid channel dropping sections. The components of the multiplexer are enclosed in a metallic housing forming a cavity surrounding the multiplexer components. Each of the hybrid-filter-hybrid sections is comprised of first and second 90 deg hybrid couplers which are connected by a pair of identical bandpass filters. Spurious waveguide energy propagation modes which would otherwise ... |
|
| Synchronous/Asynchronous Independent Single Sideband Acoustic Telemetry. |
14 FEB 1984 |
|
| Authors:
G. R. Mackelburg; S. J. Watson; A. Gordon; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An undersea communications system provides for improved data transmission capabilities. Two separate sources of information respectively modulate the upper and the lower sidebands of an acoustic carrier. The discretely modulated sidebands are simultaneously transmitted without the acoustic carrier or the acoustic carrier can be added to allow asynchronous or synchronous demodulation and use of the two modulating informations. Separation of the information in the two discretely modulated sidebands is assured ... |
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| Voice Preprocessing System Incorporating a Real-Time Spectrum Analyzer with Programmable Switched-Capacitor Filters |
JAN 1984 |
|
| Authors:
G. Knapp; MITRE CORP BEDFORD MA
|
| As part of a speaker verification program for BISS (Base Installation Security System), a test system is being designed with a flexible preprocessing system for the evaluation of voice spectrum/verification algorithm related problems. The main part of this report covers the design, construction, and testing of a voice analyzer with 16 integrating real-time frequency channels ranging from 300 Hz to 3 KHz. The bandpass filter response of each channel is ... |
|
| Evanescent Resonator Frequency Multiplier. |
03 NOV 1983 |
|
| Authors:
Joseph H. Hartley; DEPARTMENT OF THE ARMY WASHINGTON DC
|
| This invention relates to a frequency multiplier for electromagnetic waves in which multiples of the input frequency propagate, while the input frequency evaneces. A rectangular waveguide or other suitable wave conveying element with a cut-off frequency above the input frequency but below the output frequency contains the multiplying structure. The input frequency is multiplied using a post located in the waveguide or other element adjacent to the source of input ... |
|
| An Investigation of Strip Lines and Fin Lines with Periodic Stubs |
OCT 1983 |
|
| Authors:
T. Kitazawa; R. Mittra; ILLINOIS UNIV AT URBANA ELECTROMAGNETICS LAB
|
| In this paper a technique based on the network analytical formalism of electromagnetic fields is used to analyze the strip and fin lines with periodic stubs. Numerical results for the dispersion characteristics of the periodically loaded lines are presented. The effect of the loading stubs on the passband and stopband characteristics is investigated. (Author) |
|
| Optimum Filtering Required for Broadband Detection of Gaussian Processes |
22 SEP 1983 |
|
| Authors:
Ira B. Cohen; Albert H. Nuttall; NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT NEW LONDON LAB
|
| The derivation for the optimum filter required for broadband detection of Gaussian processes is presented. The performance criteria that is optimized is probability of detection for a fixed false alarm rate. It is shown by example that the optimum filter out performs the widely used Eckart filter and other filters. (Author) |
|
| Millimeter Wave Printed Circuit Mixer. |
20 SEP 1983 |
|
| Authors:
John Reindel; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A millimeter wave printed circuit mixer is disclosed which has extended RF and IF bandwidths. A dual ridge wave guide to slotline transition is utilizing to bring the RF signal into the device. The waveguide to slotline transition is terminated in first and second shorted RF slotlines formed on the bottom of a dielectric substrate and extending from the RF slotline. A microstrip LO bandpass filter terminating in a microstrip ... |
|
| Millimeter Wave Printed Circuit Mixer. |
20 SEP 1983 |
|
| Authors:
J. Reindel; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A millimeter wave printed circuit mixer is disclosed which has extended RF and IF bandwidths. A dual ridge waveguide to slotline transition is utilized to bring the RF signal into the device. The waveguide to slotline transition is terminated in first and second shorted RF slotlines formed on the bottom of a dielectric substrate and extending from the RF slotline. A microstrip LO bandpass filter terminating in a microstrip line ... |
|
| A Cost Constrained Speech Recognition Systems |
AUG 1983 |
|
| Authors:
Walter F. Davidson; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
|
| This paper describes the design, construction, and evaluation of a microprocessor-based, cost-constrained word recognition system. The system uses seven bandpass filters, logarithmically spaced, followed by envelope detectors. The final algorithm uses eight uniformly spaced time slices, and used dynamic programming for time warping, with a weighted Tchebycheff distance. This system resulted in 98% correct recognition for the ten digits, 0 - 9, of the training group, and 96% correct recognition ... |
|
| Programmable LFM Signal Processor. |
11 JUL 1983 |
|
| Authors:
Robert C. Thor; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| The linear frequency modulation signal processor may be programmed to be a matched filter for any pulse compression ratio less than or equal to the square of the number of bandpass filters. The processor is implemented by using a fast Fourier transform (FFT) for the filter bank. The implementation shown assumes digital processing at baseband using in-phase and quadrature (I and Q) channels and a FFT for the filter bank. ... |
|
| A Representation for Shape Based on Peaks and Ridges in the Difference of Low-Pass Transform |
MAY 1983 |
|
| Authors:
James L. Crowley; Alice C. Parker; CARNEGIE-MELLON UNIV PITTSBURGH PA ROBOTICS INST
|
| This paper defines a multiple resolution representation for the two- dimensional gray-scale shapes in an image. This representation is constructed by detecting peaks and ridges in the Difference of Low Pass (DOLP) transform. Descriptions of shapes which are encoded in this representation may be matched efficiently despite changes in size, orientation or position. Motivations for a multiple resolution representation are presented first, followed by the definition of the DOLP Transform. ... |
|
| Pseudo-Atmospheric Noise Generator with Control of Temporal Characteristics. |
01 MAR 1983 |
|
| Authors:
P. A. Singer; R. K. Cernius; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An improved psuedo-atmospheric noise generator includes the capability for producing noise in the VLF/LF spectrum with known amplitude probability distributions while controlling the temporal characteristics of the simulated impulses. The outputs from a number of psuedo-random bit generators are selected by a microprocessor in accordance with expected or anticipated atmospheric disturbances from a number of geographical regions. The microprocessor selected outputs are fed to a digital-to-analog converter which feeds the ... |
|
| Frequency Hopping Transceiver Multiplexer |
MAR 1983 |
361 pages |
| Authors:
Colin B. Weir; GTE PRODUCTS CORP NEEDHAM HEIGHTS MA COMMUNICATION SYSTEMS DIV
|
| This final report summarizes the activity on contract DAAK80-80-C- 0588, which investigated the concept and feasibility of a 30MHz to 88MHz frequency hopping transceiver multiplexer. An approach which uses helical resonator filters, PIN diode switched capacitors and quadrature couplers for combiner and antenna matching circuits represents the most optimistic design. (Author) |
|
| Image Enhancement of a Camouflaged Target Using Properties of Metameric Colors. |
07 JAN 1983 |
|
| Authors:
Harry C. Meyer III; DEPARTMENT OF THE ARMY WASHINGTON DC
|
| A method of discriminating the image of a camouflaged object or target from surrounding background by using the difference in the spectral distribution of radiation from the target intensity over that of the background. Enhancement is achieved by detecting reflected radiation from both the target and the background and transmitting this radiation through separate broad band filters having different frequencies. The respective filter's wavelengths are predetermined by the spectra of ... |
|
| Image Enhancement by Partially Coherent Imaging |
1983 |
|
| Authors:
William T. Rhodes; M. Koizumi; GEORGIA INST OF TECH ATLANTA SCHOOL OF ELECTRICAL ENGINEERING
|
|
| Frequency-Phase Coding Device. |
16 NOV 1982 |
|
| Authors:
Bernard L. Lewis; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| This invention relates to a doppler-tolerant pulse-compression code generator for generating a plurality of approximately orthogonal codes which will prevent radar interference and suppress jamming. These codes are generated by phase-coding the frequency-band steps and also altering the time-sequence of the frequency steps of a step-approximation to a linear FM chirp pulse. Specifically, this code generator may comprise a circuit for modulating a carrier frequency with a video pulse of ... |
|
| Fast Computation of the Difference of Low-Pass Transform |
NOV 1982 |
|
| Authors:
James L. Crowley; Richard M. Stern; CARNEGIE-MELLON UNIV PITTSBURGH PA ROBOTICS INST
|
| This paper defines the Difference of Low-Pass (DOLP) transform and describes a fast algorithm for its computation. The DOLP is a reversible transform which converts an image into a set of band-pass images. A DOLP transform is shown to require O(N sub 2) multiplies and produce O(N Log(N)) samples from an N sample image. When Gaussian low-pass filters are used, the result is a set of images which have been ... |
|
| Geomagnetic Pulsations-Production/Interpretation |
SEP 1982 |
|
| Authors:
Elwood Maple; EMMANUEL COLL BOSTON MA
|
| Work has been devoted to experimental studies of middle-latitude geomagnetic pulsations in the period range 0.2 to 50 minutes. The principal effort has been on the resonant periods of the pulsations which arise from hydromagnetic resonances in the magnetosphere. The resonant periods appear as peaks in the period distributions and frequency spectra of the pulsations. The present work utilizes polarization traces which provide continuous displays of the polarization of the ... |
|
| Equivalent Bandwidth of a General Class of Polynomial Smoothers: With Application to Bearing Tracker Random Error Evaluation |
19 JUL 1982 |
|
| Authors:
Robert A. LaTourette; NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT NEW LONDON LAB
|
| Random bearing error is a major performance measure of a sonar bearing tracker. Programs currently employed in calculating random bearing error from measured tracker bearing error data use a standard polynomial Least Mean Square Fit (LMSF) algorithm to remove an unknown time varying mean. Previously, the effect of the LMSF algorithm on the residuals of the measured tracker bearing error data was not fully accounted for. In addition, when processing ... |
|
| Powder Spectroscopy in the Infrared Spectral Region |
JUL 1982 |
|
| Authors:
V. P. Tomaselli; K. D. Moeller; FAIRLEIGH DICKINSON UNIV HACKENSACK NJ PHYSICS RESEARCH LAB
|
| Experimental work is reported in the following areas: evaluation of infrared optical properties of obscurants using reflection and transmission methods; development of instrument components for a millimeter wave spectrometer; development of laser-based instrument for the measurement of optical constants of powders using internal reflection techniques; and construction of apparatus to measure the angular distribution of infrared laser radiation scattered from infinitely long conducting wires. The following projects were completed and ... |
|
| Moving Vehicle Seismic Target Detector. |
29 JUN 1982 |
|
| Authors:
Glenn G. Clinard; Gail R. Mulhollam; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| This report describes seismic detection of a target is obtained with a geophone detecting earth vibrations caused by the actions of the target. The vibrations are wide band amplified and band-passed filtered with the pass bands being fed to the threshold detectors. The outputs of the threshold detectors are fed to a diode AND logic circuit, the output thereof indicating the presence of a target. |
|
| A FORTRAN Package for the Simulation and Spectral Analysis of a Channelized Receiver and other Systems. |
JUN 1982 |
|
| Authors:
John Salvatore Signorino; GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION
|
| This thesis describes a FORTRAN software package which simulates the RF section and slot assembly of the Air Force's High Probability Intercept Receiver (HPIR). The software package is written as a group of subroutines which can be used to simulate the HPIR or a large class of general systems consisting of cascaded two-port devices. Devices to be simulated with selected input waveforms can be actual two-ports devices whose frequency response ... |
|
| Design and Microprocessor-Based Implementation of Digital Frequency Selective Filters for Application in Terrain Roughness Identification |
APR 1982 |
98 pages |
| Authors:
K. C. Cheok; N. K. Loh; OAKLAND UNIV ROCHESTER MI CENTER FOR ROBOTICS AND ADVANCED AUTOMATION
|
| The design and implementation of microprocessor-based frequency selective filters for possible use in an on-board terrain roughness identification scheme are investigated. In the design aspect of the investigation, a systematic digital filter design procedure is developed. The effectiveness of the procedure is illustrated by several digital filter design examples. In the implementation aspect, a digital signal processing firmware (hardware and software) based on the Motorola 6802 microprocessor is developed. The ... |
|
| Delta Electrical Load Analysis C-141B JACC/CP Aircraft |
10 MAR 1982 |
|
| Authors:
G. R. Taylor; ROCKWELL INTERNATIONAL CEDAR RAPIDS IA COLLINS RADIO GROUP
|
| The installation of the provisions to accept the JACC/CP Capsule in the C -141B Aircraft causes a change to the electrical loads within the present aircraft power distribution system. The purpose of this report is to furnish a tabulation of the changes to the aircraft power system caused by this installation. |
|
| Preliminary LIDAR Backscatter Measurements |
19 FEB 1982 |
|
| Authors:
J. A. Curcio; M. A. Woytko; D. H. Leslie; NAVAL RESEARCH LAB WASHINGTON DC
|
| The work reported here represents the results of an initial NRL effort to use existing equipment to assemble a working LIDAR. The goal of the effort was to obtain both hard-target and aerosol back-scatter signals, using existing NRL equipment. To this end the effort was successful. We report our methods, results, and equipment used. We also outline our plans for improving the system in FY-82. (Author) |
|
| Airglow Imaging Studies of Natural and Artificially Induced Ionospheric Disturbances |
FEB 1982 |
|
| Authors:
Michael Mendillo; Jeffrey Baumgardner; Harlan Spence; BOSTON UNIV MA DEPT OF ASTRONOMY
|
| A low light level, image intensified airglow monitoring system has been developed for ground-based studies of 6300A airglow characteristics of equatorial plasma depletions and rocket exhaust induced ionospheric holes. The system was designed for narrow band interference filters (6 A FWHP) with interchangeable all-sky (180 deg) and narrow field (60 deg) lenses; it records images photographically using a standard 35mm camera. In addition to the morphology features capable of being ... |
|
| Inversion for t* (f) |
30 NOV 1981 |
|
| Authors:
G. M. Lundquist; I. R. Samowitz; SIERRA GEOPHYSICS INC REDMOND WA
|
| This technical report summarizes work done during the period December 1, 1980 through September 30, 1981 based upon software developed and experience gained in modeling several forms of the Q filter. This report concentrates on the inversion theory to model the Q filter and to estimate the models of each parameter. Two spectral ratio data sets are used, PP/P and receiver function rates. The PP/P data set was limited to ... |
|
| A Representation for Visual Information |
NOV 1981 |
|
| Authors:
James L. Crowley; CARNEGIE-MELLON UNIV PITTSBURGH PA ROBOTICS INST
|
| This dissertation presents a new technique for representing digital pictures. The principal benefit of this representation is that it greatly simplifies the problem of finding the correspondence between components in the description of two pictures. This representation technique is based on a new class of reversible transforms (the Difference of Low Pass or DOLP transform). A fast algorithm for computing the DOLP transform is then presented. This algorithm, called cascade ... |
|
| Design, Fabrication and Test of a Metal-Grid Angular Filter |
NOV 1981 |
167 pages |
| Authors:
John F. Pedersen; Peter W. Hannan; ROME AIR DEVELOPMENT CENTER GRIFFISS AFB NY
|
| This final report describes the design, fabrication and test of a metalgrid spatial filter. The filter is a 5 x 5 foot flat panel incorporating 4 layers of crossed wire grids in a supporting structure of dielectric skins and dielectric honeycomb material. The spatial filter passes an electromagnetic wave incident within its angular passband centered on normal incidence, but reflects the wave if it is incident beyond about 30 degrees ... |
|
| Single Channel Seismic Event Detection |
07 OCT 1981 |
|
| Authors:
Robert R. Blandford; David Racine; Raleigh Romine; TELEDYNE GEOTECH ALEXANDRIA VA SEISMIC DATA ANALYSIS CENTER
|
| Several types of seismic signal detectors have been tested on NORSAR and Pinedale, Wyoming signals buried every ten minutes in approximately 22 hours of phase-scrambled noise. All plausible detectors including human analysts operate within 0.1 mb of the mean value including the present on-line 'IBM' STA/ LTA detector, a 'Z' detector, detectors with fixed or optimum filters, a 'deflection' detector, the MARS detector, a detector which cascades a recursive digital ... |
|
| Seismic Signal Detection Algorithms |
30 SEP 1981 |
|
| Authors:
K. F. Veith; TELEDYNE GEOTECH GARLAND TX
|
| This report covers the procedures undertaken and the results obtained during an 18-month program to implement and test an automatic seismic event detection algorithm that is based on the Walsh transform. The algorithm was successfully implemented and tested on a Z80A-based microcomputer, and the system was placed in operation at the Norwegian Seismic Array (NORSAR) for on- line evaluation. The results of the system operation and effectiveness is presented. Also ... |
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Reports by Keyword(s)
BANDPASS FILTERS
