Proposed acousto-optic filter
Narrow band optical filter is electronically tunable over a large wavelength region. The filter utilizes collinear acousto-optic diffraction in an optically anisotropic media.
Harris, S. E.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Linear prediction filter analysis of relativistic electron properties at 6.6 R(E)
The relationship between relativistic electron flux variations at 6.6 R(E) and various published indices and solar wind properties is studied. An attempt is made to characterize the temporal and dimensional relationships between solar wind or magnetic indices and electron flux enhancements. It is shown that the solar wind speed upstream of the earth's magnetosphere is correlated with large increases in the flux of highly relativistic electrons at geostationary orbit.
Baker, D. N.↗
Experimental investigations on electrostatic filter lenses with wide image angles.
Constructing and evaluating electrostatic filter lenses with wide image angles for low voltage electron microscope
ELECTRON MICROSCOPE↗
The design of digital filters
Digital filter design program capable of generating discrete representations for continuous filters - digital computer
ELECTRONIC FILTER↗
Generalized snr and performance index of filters for waveform estimation.
Signal to noise ratio and performance index of filters for waveform estimation, discussing optimum mean-square filters
ELECTRIC NETWORK↗
NASA Tech Briefs, October 2004
Topics include: Relative-Motion Sensors and Actuators for Two Optical Tables; Improved Position Sensor for Feedback Control of Levitation; Compact Tactile Sensors for Robot Fingers; Improved Ion-Channel Biosensors; Suspended-Patch Antenna With Inverted, EM-Coupled Feed; System Would Predictively Preempt Traffic Lights for Emergency Vehicles; Optical Position Encoders for High or Low Temperatures; Inter-Valence-Subband/Conduction-Band-Transport IR Detectors; Additional Drive Circuitry for Piezoelectric Screw Motors; Software for Use with Optoelectronic Measuring Tool; Coordinating Shared Activities; Software Reduces Radio-Interference Effects in Radar Data; Using Iron to Treat Chlorohydrocarbon-Contaminated Soil; Thermally Insulating, Kinematic Tensioned-Fiber Suspension; Back Actuators for Segmented Mirrors and Other Applications; Mechanism for Self-Reacted Friction Stir Welding; Lightweight Exoskeletons with Controllable Actuators; Miniature Robotic Submarine for Exploring Harsh Environments; Electron-Spin Filters Based on the Rashba Effect; Diffusion-Cooled Tantalum Hot-Electron Bolometer Mixers; Tunable Optical True-Time Delay Devices Would Exploit EIT; Fast Query-Optimized Kernel-Machine Classification; Indentured Parts List Maintenance and Part Assembly Capture Tool - IMPACT; An Architecture for Controlling Multiple Robots; Progress in Fabrication of Rocket Combustion Chambers by VPS; CHEM-Based Self-Deploying Spacecraft Radar Antennas; Scalable Multiprocessor for High-Speed Computing in Space; and Simple Systems for Detecting Spacecraft Meteoroid Punctures.
Source record↗
Selectivity of notch filters using nonuniform rc lines.
Selectivity of notch filters using nonuniform RC LINES
FEEDBACK AMPLIFIER↗
Optimum homomorphic filters.
Optimum homomorphic filter analysis based on cascade representation
LINEAR SYSTEM↗
Inductorless filters
Gyrator-capacitor network used in production of inductorless filters with RC-ACTIVE networks
NETWORK SYNTHESIS↗
Identification of frequency components in electron content data by nonlinear filtering
A nonlinear filtering technique, called multiplicative homomorphic signal processing, is used to identify three groups of frequency components in electron content data. The first group of components results from the modulation of solar activity produced by the 27 day solar rotation. The second group is of lunar origin. The lunar frequencies are caused by nonlinear processes which probably occur in the dynamo region. The precise nature of these processes is not fully understood. The third group of frequency components, with a fundamental period of 13.9 days, has an unknown origin.
Bernhardt, P. A.↗
Long-Wavelength-Infrared Hot-Electron Transistor
Dark current reduced by energy-discriminating quantum filter. Very long-wavelength-infrared hot-electron transistor developed. Device detects photons at wavelengths around 16 micrometers. Comprises photodector integrated with energy-discriminating quantum filter in multiple-quantum-well structure. Made of variously doped and undoped layers of GaAs (quantum wells) and Al(x)Ga(1-x)As (barriers between wells). In transistor, bound-to-continuum GaAs/Al(x)Ga(1-x)As multiple-quantum-well infrared photodectors (QWIP) serves as photosensitive emitter. Wide quantum well serves as base, and there is thick barrier between base and collector. Combination of barrier and base quantum well acts as energy-discriminating filter: electrons with higher energies pass through filter to collector, those with lower energies blocked and diverted from output-current path through base contact.
Gunapala, Sarath D.↗
Solution of nonlinear algebraic equations characteristic of filter circuits Summary technical report
Digital computer program developed for solving nonlinear algebraic equations characteristic of filter circuits
COMPUTER PROGRAM↗
Experimental research on communication systems subject to intersymbol interference
Binary communication systems for determining performance error probability of channel filters and modulation schemes
COMPUTER SIMULATION↗
Filtering techniques for noise suppression in quasi-balanced circuits
Filtering techniques for noise suppression in quasi-balanced circuits
NOISE REDUCTION↗
Active and passive multiplication of RC time constants for subaudio frequency integrated filters.
Active and passive multiplication of RC time constants for subaudio frequency integrated filters
RC NETWORK↗
RC filters with staggered notch frequencies.
RC filter with staggered notch frequencies for ease of adjustment and maintenance
RC NETWORK↗
Electromagnetic compatibility design guideline for STADAN
Procedures for achieving electromagnetic compatibility in electronic and electrical equipment for aerospace ground stations are investigated. The application of shielding theory to good design is treated and standards of good practice are outlined for bonding, grounding, wiring, and cabling. Some aspects of filter design are explained, and suggestions are given for the application of filters to electronic and electrical equipment.
Cowdell, R. B.↗
Second-Generation Multi-Angle Imaging Spectroradiometer
A report discusses an early phase in the development of the MISR-2 C, a second, improved version of the Multi-angle Imaging SpectroRadiometer (MISR), which has been in orbit around the Earth aboard NASA's Terra spacecraft since 1999. Like the MISR, the MISR-2 would contain a pushbroom array of nine charge-coupled- device (CCD) cameras one aimed at the nadir and the others aimed at different angles sideways from the nadir. The major improvements embodied in the MISR-2 would be the following: A new folded-reflective-optics design would render the MISR-2 only a third as massive as the MISR. Smaller filters and electronic circuits would enable a reduction in volume to a sixth of that of the MISR. The MISR-2 would generate images in two infrared spectral bands in addition to the blue, green, red, and near-infrared spectral bands of the MISR. Miniature polarization filters would be incorporated to add a polarization-sensing capability. Calibration would be performed nonintrusively by use of a gimbaled tenth camera. The main accomplishment thus far has been the construction of an extremely compact all-reflective-optics CCD camera to demonstrate feasibility.
Macenka, Steven↗