RC filters with staggered notch frequencies
Resistance capacitance band-stop filters with staggered notch frequencies, and design data on stop-bandwidth, stop-band attenuation, and frequencies
BAND PASS FILTER↗
SEARCH · Engineering Papers
Results for “bandwidth”
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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Research and development of an optimized laboratory speech compression system for spacecraft application. Task 6 - Space mission applications study
Narrow bandwidth speech communication processing system for lunar and interplanetary, missions and characteristics of onboard noise sources
NOISE↗
Research in picture processing.
Digital computer research program for reducing bandwidth schemes and quality for picture transmission
DIGITAL SIMULATION↗
The compensated balun.
Impedance transforming compensated balance to unbalanced line transformer /balun/, discussing bandwidths
ELECTRIC IMPEDANCE↗
PCM picture transmission.
PCM picture transmission, pseudorandom scanning, noise, bandwidth compression and digital simulation
BANDWIDTH↗
Multiplier phototubes as quantum counters.
Unusual optical detection characteristics in multiplier phototube when monitoring circuit bandwidth is extended
PHOTOMULTIPLIER↗
Analysis and simulation of data compression techniques.
Data compression for analog signal transmission with smaller bandwidth requirement obtained from reduced signal redundancy and simulation of techniques
ANALOG DATA↗
Avalanche-photodiode frequency response.
Short circuit photocurrent of avalanche photodiode, determining frequency response and multiplication effect on bandwidth
BANDWIDTH↗
Means for improving apparent television resolution.
TV system resolution improvement without bandwidth increase, discussing accuracy of random alphabetic characters
IMAGERY↗
The development of inflatable array antennas
Inflatable array antennas are being developed to significantly reduce the mass, the launch vehicle's stowage volume, and the cost of future spacecraft systems. Three inflatable array antennas, recently developed for spacecraft applications, are a 3.3 m x 1.0 m L-band synthetic-aperture radar (SAR) array, a 1.0 m-diameter X-band telecom reflectarray, and a 3 m-diameter Ka-band telecom reflectarray. All three antennas are similar in construction, and each consists of an inflatable tubular frame that supports and tensions a multi-layer thin-membrane RF radiating surface with printed microstrip patches. The L-band SAR array achieved a bandwidth of 80 MHz, an aperture efficiency of 74%, and a total mass of 15 kg. The X-band reflectarray achieved an aperture efficiency of 37%, good radiation patterns, and a total mass of 1.2 kg (excluding the inflation system). The 3 m Ka-band reflectarray achieved a surface flatness of 0.1 mm RMS, good radiation patterns, and a total mass of 12.8 kg (excluding the inflation system). These antennas demonstrated that inflatable arrays are feasible across the microwave and millimeter-wave spectrums. Further developments of these antennas are deemed necessary, in particular, in the area of qualifying the inflatable structures for space-environment usage.
Inflatable array antennas↗
State Estimation of International Space Station Centrifuge Rotor With Incomplete Knowledge of Disturbance Inputs
This thesis develops a state estimation algorithm for the Centrifuge Rotor (CR) system where only relative measurements are available with limited knowledge of both rotor imbalance disturbances and International Space Station (ISS) thruster disturbances. A Kalman filter is applied to a plant model augmented with sinusoidal disturbance states used to model both the effect of the rotor imbalance and the 155 thrusters on the CR relative motion measurement. The sinusoidal disturbance states compensate for the lack of the availability of plant inputs for use in the Kalman filter. Testing confirms that complete disturbance modeling is necessary to ensure reliable estimation. Further testing goes on to show that increased estimator operational bandwidth can be achieved through the expansion of the disturbance model within the filter dynamics. In addition, Monte Carlo analysis shows the varying levels of robustness against defined plant/filter uncertainty variations.
SINUSOIDAL DISTURBANCE STATES↗
FQPSK Developments Recommended for CCSDS Standardization by NASA/JPL
In 1992, international space agencies became concerned that increasing frequency band congestion, together with attempts by the mobile telephone industry to obtain additional bandwidth, would result in substantially more interference incidents.
modulation Feher's quadrature phase shift keying b↗
Design and Measurements of Dual-Polarized Wideband Constant-Beamwidth Quadruple-Ridged Flared Horn
A quad-ridged, flared horn achieving nearly constant beamwidth and excellent return loss over a 6:1 frequency bandwidth is presented. Radiation pattern measurements show excellent beamwidth stability from 2 to 12 GHz. Measured return loss is > 10 dB over the entire band and > 15 dB from 2.5 to 11 GHz. Using a custom physical optics code, system performance of a radio telescope is computed and predicted performance is average 70% aperture efficiency and 10 Kelvin of antenna noise temperature.
decade bandwidth↗
Progress on the Development of the Optical Communications Demonstrator
The Optical Communications Demonstrator (OCD) is a laboratory-based lasercom demonstration terminal designed to validate several key technologies, including beacon acquisition, high bandwidth tracking, precision beam pointing, and point-ahead compensation functions.
CCD↗
Analysis of Handling Qualities and Power Consumption for Urban Air Mobility (UAM) eVTOL Quadrotors with Degraded Heave Disturbance Rejection and Control Response
A piloted handling qualities study of urban air mobility (UAM) electric vertical take-off and landing (eVTOL) quadrotors was performed utilizing the Vertical Motion Simulator (VMS) facility at NASA Ames Research Center. Rotor speed and variable pitch-controlled variants of a six-passenger conceptual design vehicle were assessed with different levels of degradation to control response and disturbance rejection bandwidth (DRB) in the heave axis. In previous work, preliminary trends across several handling quality rating categories reflected the effects of these degradations. Additionally, the impact of using different test standards and turbulence on the ratings were discussed. This paper elaborates on those results, but also provides insight into unexpected trends observed during the study including: a disharmony in attitude response, subpar ratings for the baseline Level 1 performance vehicle, and excessive drift and yaw couplings observed in a lateral reposition maneuver. Moreover, shortcomings of the handling quality scales and comparisons of power consumption among the vehicles in the various test conditions are presented.
Handling Qualities↗
GETTING THE MOST OUT OF AEROSPACE TELEMETRY
Adaptive transmission system, capable of varying power or bandwidth or both, to combat changing environmental conditions and to increase efficiency of operation
TELEMETRY↗
Field-effect transistor improves electrometer amplifier
An electrometer amplifier uses a field effect transistor to measure currents of low amperage. The circuit, developed as an ac amplifier, is used with an external filter which limits bandwidth to achieve optimum noise performance.
Munoz, R.↗
Masers for the telstar satellite communications experiment
This paper discusses the design and characteristics of ruby traveling-wave masers operating at 4 gc. These masers, characterized by an average gain of ≈35 db over a bandwidth of 25 mc, are equipped with waveguide input transmission lines, rather than the previously employed coaxial cables. This change results in an over-all noise temperature of 3.5°K for these devices, rather than the 10°K exhibited by earlier masers. The maser noise temperature now closely approximates sky temperatures, which set the ultimate limit on earthbound receiver sensitivity. The improvements to be had by further reduction in amplifier noise are therefore almost negligible. A less well known maser property, i.e., its freedom from distortion, even when driven well into gain saturation, is discussed.
TELSTAR SATELLITE↗