Keyword: Transmissions

Briefs: Photonics/Optics
Self-Nulling Beam Combiner Using No External Phase Inverter

A self-nulling beam combiner is proposed that completely eliminates the phase inversion subsystem from the nulling interferometer, and instead uses the intrinsic phase shifts in the beam splitters. Simplifying the flight instrument in this way will be a valuable enhancement of mission...

Briefs: Electronics & Computers
Enabling IP Header Compression in COTS Routers via Frame Relay on a Simplex Link

NASA is moving toward a network-centric communications architecture and, in particular, is building toward use of Internet Protocol (IP) in space. The use of IP is motivated by its ubiquitous application in many communications networks and in available commercial...

Briefs: Software

Deep space communications over noisy channels lead to certain packets that are not decodable. These packets leave gaps, or bursts of erasures, in the data stream. Burst erasure correcting codes...

Briefs: Software

Short-block low-density parity-check (LDPC) codes of a special type are intended to be especially well suited for potential applications that include transmission of command and control data, cellular...

Briefs: Electronics & Computers
High-Performance CCSDS Encapsulation Service Implementation in FPGA

The Consultative Committee for Space Data Systems (CCSDS) Encapsulation Service is a convergence layer between lower-layer space data link framing protocols, such as CCSDS Advanced Orbiting System (AOS), and higher-layer networking protocols, such as CFDP (CCSDS File Delivery...

Briefs: Photonics/Optics
High-Speed Operation of Interband Cascade Lasers

Optical sources operating in the atmospheric window of 3–5 μm are of particular interest for the development of free-space optical communication link. It is more advantageous to operate the free-space optical communication link in 3–5-μm atmospheric transmission window than at the telecom...

Briefs: Physical Sciences
Simplified Vicarious Radiometric Calibration

A measurement-based radiance estimation approach for vicarious radiometric calibration of spaceborne multispectral remote sensing systems has been developed. This simplified process eliminates the use of radiative transfer codes and reduces the number of atmospheric assumptions required to perform...

Briefs: Mechanical & Fluid Systems
Compact, Lightweight Servo-Controllable Brakes

Compact, lightweight servo-controllable brakes capable of high torques are being developed for incorporation into robot joints. A brake of this type is based partly on the capstan effect of tension elements, which is described by the well known equation

Briefs: Energy
In recent years, better stabilizer formulations for ethylene vinyl-acetate have been developed, giving more confidence in the long-term stability of PV packaging materials. Because of this, some manufacturers have stopped using Ce-doped glass. National Renewable Energy Laboratory researchers studied Ce-free glass.
Briefs: Information Technology
Algorithms for Learning Preferences for Sets of Objects

A method is being developed that provides for an artificial-intelligence system to learn a user’s preferences for sets of objects and to thereafter automatically select subsets of objects according to those preferences. The method was originally intended to enable automated selection,...

Articles: Sensors/Data Acquisition

The ability to make real-time decisions based on pressure, temperature, or flow measurements while a process is running can provide significant advantages in a measurement and control...

Application Briefs: Photonics/Optics

The ubiquitous techniques of fluorescence and Raman imaging and spectroscopy rely heavily on spectrally precise, high-quality and high-throughput optical filter technologies. As both fluorescence and Raman-based...

Briefs: Electronics & Computers
A 311-GHz Fundamental Oscillator Using InP HBT Technology

This oscillator uses a single-emitter 0.3-μm InP heterojunction bipolar transistor (HBT) device with maximum frequency of oscillation (fmax) greater than 500 GHz. Due to high conductor and substrate losses at submillimeter-wave frequencies, a primary challenge is to...

Briefs: Mechanical & Fluid Systems
Offset Compound Gear Drive

The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth...

Briefs: Electronics & Computers

A new space-qualified, high-power, high-efficiency, K-band traveling-wave tube amplifier (TWTA), shown in the figure, will provide high-rate, high-capacity, direct-to-Earth communications for science data...

Briefs: Information Technology

Some non-traditional signal constellations have been proposed for transmission of data over the Additive White Gaussian Noise (AWGN) channel using such channel-capacity-approaching codes as low-density...

Articles: Energy

With auto sales down as much as 40 percent, it can feel to some like the industry is coming apart. But a "revolution in fasteners" may soon help bridge the gap to greener...

Briefs: Electronics & Computers

The L-3 Communications Electron Technologies, Inc. Model 999HA traveling-wave tube (TWT), was developed for use as a high-power microwave amplifier for high-rate transmission of data and video signals from...

Briefs: Information Technology
ICER-3D Hyperspectral Image Compression Software

Software has been developed to implement the ICER-3D algorithm. ICER-3D effects progressive, threedimensional (3D), wavelet-based compression of hyperspectral images. If a compressed data stream is truncated, the progressive nature of the algorithm enables reconstruction of hyperspectral data at...

Briefs: Physical Sciences
Integrity Monitoring of Mercury Discharge Lamps

Mercury discharge lamps are critical in many trapped ion frequency standard applications. An integrity monitoring system can be implemented using end-of-life signatures observed in operational mercury discharge lamps, making it possible to forecast imminent failure and to take action to mitigate...

Briefs: Materials

New designs, and materials appropriate for such designs, are under investigation in an effort to develop coronagraph occulting masks having broad-band spectral characteristics...

Briefs: Electronics & Computers
Spacesuit Data Display and Management System

A prototype embedded avionics system has been designed for the next generation of NASA extra-vehicular-activity (EVA) spacesuits. The system performs biomedical and other sensor monitoring, image capture, data display, and data transmission. An existing NASA Phase I and II award winning design for an...

Briefs: Electronics & Computers
Radiometer on a Chip

Submillimeter-wave radiometers have traditionally been built by packaging each chip with a distinct function separately, and then combining the packaged chips to form subsystems. Instead of packaging one chip at a time, the radiometer on a chip (ROC) integrates whole wafers together to provide a robust, extremely powerful...

Briefs: Mechanical & Fluid Systems

T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in...

Briefs: Materials

Rectangular-waveguide inserts that are made of non-ferromagnetic metals and are sized and shaped to function as notch filters have been conceived as reference standards for use in...

Briefs: Manufacturing & Prototyping
Silicon Wafer-Scale Substrate for Microshutters and Detector Arrays

The silicon substrate carrier was created so that a large-area array (in this case 62,000+ elements of a microshutter array) and a variety of discrete passive and active devices could be mounted on a single board, similar to a printed circuit board. However, the density and...

Briefs: Mechanical & Fluid Systems

Thin-layered structures containing arrays of micromachined horns, denoted solid micro-horn arrays (SMIHAs), have been conceived as improved means of matching acoustic impedances between...

Briefs: Information Technology
Minimizing Input-to-Output Latency in Virtual Environment

A method and apparatus were developed to minimize latency (time delay) in virtual environment (VE) and other discrete-time computer-based systems that require real-time display in response to sensor inputs. Latency in such systems is due to the sum of the finite time required for...

Briefs: Electronics & Computers

A method has been proposed to increase the degree of synchronization of a radio receiver with the phase of a suppressed carrier signal modulated with a binary-phase-shift-keying (BPSK) or...