SEARCH · Search NASA
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Resistance bridge device incorporates a potentiometer, switches, and a null detector to calibrate high potential dividers under high voltage operation conditions. Calibration can be performed with this device in less than 1 minute at an accuracy of 0.001 percent.
Laser activated ultraprecision ranging apparatus interfaced with a computer determines point coordinates on a photograph. A helium-neon gas CW laser provides collimated light for a null balancing optical system. This system has no mechanical connection between the ranging apparatus and the photograph.
Dual-channel microwave insertion loss test set which incorporates power meter coaxial thermistors with dc nulling scheme
Laser frequency stabilization methods are based on a frequency discriminant which generates an unambiguous deviation signal used for automatic stabilization. Closed-loop control stabilizes cavity length at a null point. Some systems have a stabilized ring laser using a piezoelectric dither and others use a Doppler gain tube.
Compact bridge circuit measures sensitive and accurate conductance of low-conductivity electrolyte solutions. The bridge utilizes a phase sensitive detector to obtain a linear deflection of the null indicator relative to the measured conductance.
Video synchronization processor overcomes poor signal-to-noise ratio which occurs during adverse signal conditions caused by flame attenuation, antenna pattern nulls, and near-horizon tracking. The system maintains sync lock far below the point where excessive noise would normally render the video useless.
Optical detector using length of single mode optical waveguide with photodetector at output for null detection
Prototype precision bolometer calibration bridge is manually balanced device for indicating dc bias and balance with either dc or ac power. An external galvanometer is used with the bridge for null indication, and the circuitry monitors voltage and current simultaneously without adapters in testing 100 and 200 ohm thin film bolometers.
System that substitutes solar cells directly in the path of the radiation incident on the test volume and uses a dc bridge-null system was developed. The solar cell is affixed to a heat sink mounted on each of three arms for each solar lamp. Control of the radiation from the solar lamps is automatic.
Flight test of electrostatic accelerometer which eliminates null bias problem
Null interference rejection for navigation system in aircraft-satellite link
Expanding solutions of Einstein-Maxwell equations in D class spaces admitting null and nonnull electromagnetic field
Brewster null in reflections of Explorer 35 telemetry transmissions from lunar surface, discussing radiation reflection properties of lunar maria and Flamsteed area
Spectral null from spectral characteristics and statistical properties of PCM signals used to estimate SNR
Irregular regions in Antarctic ionosphere from Polar Ionosphere Beacon Satellite S-66 recordings, obtaining irregularities density from nulls clarity
Test methods for telescope mirror, discussing polishing, monitoring by Hartmann test and visual null test
Einstein equations for empty space applied to degenerate gravitational fields with twisting rays, admitting shear-free twisting congruence of null geodesics
Space research centrifuge counteracting null gravity physiological deconditioning, discussing linear and angular accelerations sensitivity and deconditioning effect on reentry task performance