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GSPS DACs Enable Ultra-Wide Bandwidth Applications

To meet the increasing capacity demand of mobile customers, the emerging E-band market requires wider bandwidth capabilities compared to traditional microwave backhaul wireless architectures. Due to increased capacity, 2-GHz E-band systems will be needed in the near future. This white paper covers the demands of current E-band point-to-point systems, and how Analog Devices’ high-speed digital-to-analog converters (DACs) provide the necessary bandwidth and sampling frequencies to support them.

Posted in: White Papers, Electronics, Electronics & Computers, Data Acquisition, Sensors

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CMOS-Compatible Ohmic Contact RF MEMS Switch

Lyndon B. Johnson Space Center, Houston, Texas Radio frequency (RF) microelectromechanical system (MEMS) switches have advantages over their solid-state counterparts. However, ohmic contact MEMS devices face several significant limitations, preventing entry into the mass market. These limitations are cost, reliability, packaging, and integration.

Posted in: Briefs, Electronics, Electronics & Computers, Microelectromechanical devices, Radio equipment, Switches

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Miller-Jogging for Synthesizer Lock Algorithm Extension

NASA’s Jet Propulsion Laboratory, Pasadena, California The University of California Los Angeles (UCLA) has developed a wide range of CMOS (complementary metal–oxide–semiconductor) phase lock loop (PLL) chips with self-healing/self-calibration capabilities, allowing them to adapt, on the fly, to changes in temperature and other environment parameters. All CMOS PLLs typically have three major settings that self-healing and calibration can adjust: VCO (voltage controlled oscillator) coarse tuning, divider tuning, and CML (current mode logic) tuning. Previous work done at UCLA uses these “knobs” or settings exclusively to self-lock a PLL. Locking criteria is established by monitoring the control voltage with an analog-to-digital converter (ADC) to see if the PLL loop is settled in the middle of the range (locked), or sitting at the ground or supply (unlocked).

Posted in: Briefs, Electronics, Electronics & Computers, Mathematical models, Semiconductors

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Deployable Antenna Circuit Board Material Design and Fabrication Process

This technology has applications in solar arrays for small satellites.The Integrated Solar Array and Reflectarray (ISARA) antenna requires a rugged circuit board material that will meet the following requirements: (1) remains sufficiently flat over the required operating temperature range with solar cells mounted, and under full solar illumination, including heat dissipation due to ≈30% efficiency solar cells; (2) provides a sufficiently high-quality RF-grade circuit board material needed to print the reflectarray antenna; (3) is sufficiently thin (<2.5 mm) to fit within the available stowage volume; and (4) has low mass density (≈5 kg/m2).

Posted in: Briefs, TSP, Electronics, Electronics & Computers, Antennas, Integrated circuits, Fabrication

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Rigorous Antenna Noise Temperature Calculation Method for International Space Station Visiting Spacecraft

Lyndon B. Johnson Space Center, Houston, Texas The temperature of the orbiting space station’s Sun-facing side could be up to 250 °F (≈120 °C) and will be a significant antenna noise temperature contributor for visiting spacecraft communication and tracking systems during rendezvous. The conventional antenna noise temperature calculation does not take into account the space station reflection effects, and results in an underestimated antenna and system noise temperature. Thus, the visiting spacecraft communication and tracking system performance could be overestimated during rendezvous.

Posted in: Briefs, Electronics & Computers, Electronics & Computers, Software, Antennas, Telecommunications, Thermodynamics, Noise, Spacecraft

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Recurring Anomaly Detection System (ReADS)

Ames Research Center, Moffett Field, California NASA Engineering & Safety Center (NESC) subject matter experts analyze records in various International Space Station and shuttle databases to identify recurring anomalies. The key problems these experts face in analyzing such database records are:

Posted in: Briefs, Electronics & Computers, Electronics & Computers, Software, Analysis methodologies, Data acquisition and handling, Spacecraft

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Method for Automatic Optimization of Yaw Maneuvers for Orbiting Space Vehicles

Lyndon B. Johnson Space Center, Houston, Texas A new method for optimizing yaw attitude maneuvers on the International Space Station (ISS) was developed. Docking and undocking operations often require 180° yaw rotations, which are the most common large maneuvers on the ISS. When optimized, some large maneuvers, previously performed using thrusters, could be performed using control moment gyroscopes (CMGs) or with significantly reduced thruster firings. The ability to perform a non-propulsive or low-propulsive 180° yaw maneuver on the ISS has been proven through the zero propellant maneuver (ZPM) and the optimal propellant maneuver (OPM). The ZPM and OPM were created by Draper Laboratory using the computational approach. Each maneuver is unique, and can only be calculated on the ground because significant computer resources are needed for the calculations.

Posted in: Briefs, Electronics & Computers, Electronics & Computers, Software, Optimization, Simulation and modeling, Attitude control, Spacecraft guidance, Spacecraft

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