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Dynamic Range Enhancement of High-Speed Data Acquisition Systems

Reversible non-linear amplitude compression is used. John H. Glenn Research Center, Cleveland, Ohio The innovation is a technique to overcome hardware limitations of common high-speed data acquisition systems in order to be able to measure electronic signals with high dynamic range, wide bandwidth, and high frequency.

Posted in: Electronics & Computers, Briefs, TSP

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HALT Technique to Predict the Reliability of Solder Joints in a Shorter Duration

This methodology can reduce product development cycle time for improvements to packaging design qualification. NASA’s Jet Propulsion Laboratory, Pasadena, California The Highly Accelerated Life Testing (HALT) process subjects test articles to accelerated combined environments of thermal, dynamic, voltage, and current to find weak links in a given product design. The technique assesses fatigue reliability of electronic packaging designs used for long-duration deep space missions by testing using a wide temperature range (–150 to +125 °C), and dynamic acceleration range of up to 50g. HALT testing uses repetitive, multiple-axis vibration combined with thermal cycling on test articles to rapidly precipitate workmanship defects, manufacturing defects, and thermal cycling-related weak links in the design. This greatly reduces the product development time by rapidly finding problems and qualifying the packaging design quickly. Test vehicles were built using advanced electronic package designs using the surface mount technology process.

Posted in: Electronics & Computers, Briefs, TSP

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GaN Schottky Diode-Based Frequency Multiplier

New GaN fabrication process has been applied to the design fabrication and tests of frequency doublers and triplers. NASA’s Jet Propulsion Laboratory, Pasadena, California State-of-the-art GaAs Schottky diode technology, which is being used for local oscillators (LOs) in heterodyne receivers and transmitters for radar applications, has limitations in terms of power-handling capabilities. That makes it difficult to generate necessary LO power to drive multi-pixel heterodyne receivers beyond 500 GHz, and to extend the operation frequency of single-pixel receivers beyond 2 THz up to 4.7 THz (63 μm OI line).

Posted in: Electronics & Computers, Briefs

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Steady-State Thermal Test Methodology

This method allows the production of multiple test points from a single test. John F. Kennedy Space Center, Florida This innovation provides the following thermal properties data from a single steady-state test run: the effective thermal conductivity value (ke) for the full temperature difference, and multiple thermal conductivity values (λ) for intermediate temperatures. The test specimen (or material) is instrumented with one or more intermediate temperature sensors to allow the calculation of the multiple λ data points within the material and through its thickness. The methodology is particularly effective when coupled with any of the cryogenic boil-off calorimetry instruments (cryostats) developed by the Cryogenics Test Laboratory at NASA-KSC.

Posted in: Physical Sciences, Briefs, TSP

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Silicon Carbide Power Processing Unit for Hall Effect Thrusters

Prototype achieved 96.5% peak efficiency. John H. Glenn Research Center, Cleveland, Ohio A high-efficiency, rad-hard, 3.5-kW SiC power supply was developed for the power processing unit (PPU) of Hall effect thrusters. This work specifically targets the design of a PPU power supply for the HiVHAC (High Voltage Hall Accelerator) thruster. The PPU power supply under development utilizes components that were irradiated under TID (total ionizing dose) conditions to greater than 3 Mrad with little to no change in device performance.

Posted in: Physical Sciences, Briefs, TSP

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Intensity-Calibrated Hydrogen Flame Spectrum

Knowing the intensity spectrum of a hydrogen fire helps in evaluating fire detection methods. John F. Kennedy Space Center, Florida The National Aeronautics and Space Administration (NASA) uses large quantities of liquid hydrogen and has expended significant effort in the development, testing, installation, and maintenance of hydrogen fire detectors based on ultraviolet, near-infrared, mid-infrared, and/or far-infrared flame emission bands. Yet, prior to this work, there was no intensity-calibrated broadband hydrogen-air flame spectrum in the literature, making it difficult to compare the merits of different radiation-based hydrogen fire detectors.

Posted in: Physical Sciences, Briefs, TSP

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Exciting and Detecting Electromagnetic Energy in a High-Temperature Microwave Cavity

This weak-coupling approach can be used by industry for temperature-dependent dielectric measurements of high-value materials. NASA’s Jet Propulsion Laboratory, Pasadena, California There is a need to perform accurate, high-temperature, complex dielectric constant measurements at microwave frequencies on materials, such as those on the surface of Venus (surface temperature 460 °C). One approach is to excite and detect a TE10n mode resonance in a waveguide cavity heated in a high-temperature furnace. The standard way is to use commercial high-temperature transition adapters attached to cavity end plates containing small iris holes that weakly couple microwave energy into and out of the cavity. These high-temperature transition adapters are not simple to make, and are rather large in size. The addition of the transition adapter units to the waveguide cavity leads to a long combined system that in many cases makes it difficult, if not impossible, to insert in conventional high-temperature furnaces.

Posted in: Physical Sciences, Briefs, TSP

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