Electrical/Electronics

System and Method for Transferring Telemetry Data Between a Ground Station and a Control Center

Goddard Space Flight Center, Greenbelt, Maryland The Lunar Reconnaissance Orbiter (LRO) employs many advanced innovations developed at NASA’s Goddard Space Flight Center and in collaboration with other organizations. The applications and benefits for these technologies are advantageous for many other industries as well. One of those technologies is the Space Link Extension Return Channel Frames (SLE-RCF) software library. This software library enables a mission control center to receive telemetry frames from a ground station. The technology implements the SLE-RCF protocol as defined by the Consultative Committee for Space Data Systems (CCSDS). Software routines can be reused from mission to mission.

Posted in: Briefs, Electronics & Computers, Electronics & Computers, Software

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Noise Analysis in Precision Analog Designs

There are articles explaining component-level noise analysis for amplifiers or for analog-to-digital converters (ADCs), but very few that explain how to budget noise or analyze noise from the system level. This paper reviews the basics of noise analysis in precision designs, relates those calculations to system-level specifications such as sensitivity, dynamic range, and resolution, and answers some of the big questions about low-noise design.

Posted in: White Papers, Electronic Components, Electronics, Electronics & Computers, Semiconductors & ICs

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Integrated Circuit for Radio Astronomy Correlators Supporting Large Arrays of Antennas

NASA’s Jet Propulsion Laboratory, Pasadena, California Radio telescopes that employ arrays of many antennas are in operation, and ever-larger ones are being designed and proposed. Signals from the antennas are combined by cross-correlation. While the cost of most components of the telescope is proportional to the number of antennas, N, the cost and power consumption of cross-correlation are proportional to N2, and dominate at sufficiently large N. As radio telescopes get larger, there is a need to provide digital-signal-processing electronics that are smaller and less power-hungry than would be implied by the extrapolation of existing designs.

Posted in: Briefs, Electronics & Computers, Software

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Fabrication of Silicon-Leg Isolated Bi-Cr Thermopiles

Goddard Space Flight Center, Greenbelt, Maryland The objective of this innovation was to develop a methodology of fabricating thermopile detectors using standard semiconductor fabrication techniques. The goal was to develop a fabrication process that minimized the roughening of the Si legs during patterning of the metallic couples, and to enable delineation of the Si legs without the use of highly toxic or carcinogenic chemicals. Another key requirement was at least 50% optical absorbance across the spectral band.

Posted in: Briefs, Electronics & Computers

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Current Source Logic Gate

John H. Glenn Research Center, Cleveland, Ohio High-temperature electronic integrated circuits have been demonstrated in silicon carbide (SiC) depletion mode MESFETs. This process is only capable of producing depletion mode n-channel MESFET transistors. With only this type of transistor, designing a logic gate is a challenge. A previous logic gate design that can be constructed in the current process has performed well. This invention improves upon the previous design by increasing output voltage range and decreasing the physical layout size of a logic gate. This logic gate circuit consists of depletion mode MESFET/JFET transistors and resistors that can be constructed with SiC depletion mode n-channel MESFETs.

Posted in: Briefs, Electronics & Computers

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Design of Double Layer Rectenna Array for Fault Isolation of Schottky Diode in Operation Beyond V-Band Frequencies

Langley Research Center, Hampton, Virginia Microwave power transmission using rectenna technology has attracted a strong interest in conjunction with wireless electric power delivery to infrastructure and subjects located at a remote place. A typical rectenna, which is a major component of the wireless power transmission technology, consists of an antenna, a Schottky diode, and low-pass filters for low-frequency electromagnetic wave isolation in the device. To obtain high efficiency, an electromagnetic wave is collected through a high-resonance antenna, and the AC mode of coupled wave energy is delivered to a Schottky diode that rectifies AC power into DC power. By connecting rectennas in series or parallel, or in mixed way — as well as enlarging the receiving area — the rectenna array can capture microwave energy into a desirable mode of high power.

Posted in: Briefs, Electronics & Computers

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The Advantages of LWIR SLS Thermal Cameras

A relatively new type of photon detector material for infrared cameras offers a solution for scientists and engineers who need to record fast thermal transients or capture crisp still images of high speed objects or events. This material, called Type II Strained Layer Superlattice, or SLS, can match or exceed most of the performance of analogous detector materials such as indium antimonide (InSb) or mercury cadmium telluride (MCT). This article compares LWIR SLS detectors to MWIR InSb and LWIR MCT detectors, with specific attention to their integration times, temperature ranges, filtering needs, and uniformity.

Posted in: White Papers, Aeronautics, Defense, Electronics & Computers

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