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Improved Magnetic Sensor Based on Giant Magneto-Impedance

A low-power, highly stable electronic sensor circuit for measuring a small change in the ambient magnetic field with high sensitivity exploits the giant magneto-impedance (GMI) effect, in which the radio-frequency (RF) impedance of a fiber made of a suitably formulated material varies with the externally generated magnetic field to which it is exposed. The GMI effect has been observed in fibers thinner than a human hair made of amorphous (in the sense of lacking crystalline structure) alloys of cobalt, iron, silicon, and boron.

Posted in: Briefs, Electronics & Computers, Sensors and actuators, Fibers
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Progress in Canted Sector Antennas and Non-Periodic Arrays

Progress has been made in a continuing effort to develop low-geometricprofile, wide-frequency-band microwave antennas intended for incorporation into wide-band aperiodic arrays for use in high-speed communications. The effort has produced improved designs for canted sector antennas, cost-effective approximations of random arrays of such antennas, and software for simulating the performances of such antennas and arrays.

Posted in: Briefs, Electronics & Computers, Antennas, Telecommunications
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Photonic Analog-to-Digital Converters

Early steps have been taken toward the development of analog-to-digital converters (ADCs) that would incorporate photonic quantizers based on the technology of InP semiconductors. These photonic ADCs are intended to overcome the sampling speed and temporal resolution limitations of state-of-the-art all-electronic ADCs, so that outputs of radar and other sensor systems at frequencies as high as tens of gigahertz could be sampled directly, without need for analog signal processing to effect down-conversion in frequency prior to sampling.

Posted in: Briefs, Electronics & Computers, Electronic equipment, Radar, Sensors and actuators, Semiconductors
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Miniature Hyperspectral Sensors for Imaging on Small UAVs

As unmanned vehicles get smaller and smaller, operational expectations and mission objectives demand a much broader array of platform capabilities — a necessity even with reduced payloads requiring less weight, smaller size, and less power consumption. An interesting dichotomy exists between the need for increasing amounts of valuable information and the operational ability to capture and synthesize this information in real time.

Posted in: Briefs, Photonics, Imaging, Sensors and actuators, Unmanned aerial vehicles
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Photonic Analog-to-Digital Converters

Early steps have been taken toward the development of analog-to-digital converters (ADCs) that would incorporate photonic quantizers based on the technology of InP semiconductors. These photonic ADCs are intended to overcome the sampling speed and temporal resolution limitations of state-ofthe- art all-electronic ADCs, so that outputs of radar and other sensor systems at frequencies as high as tens of gigahertz could be sampled directly, without need for analog signal processing to effect down-conversion in frequency prior to sampling.

Posted in: Briefs, Photonics, Electronic equipment, Radar, Sensors and actuators, Semiconductors
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Photonic-Crystal-Based Devices for Commercial Applications

Several analog-to-digital converter (ADC) devices and part of a multispectral receiver have been designed, fabricated, and tested to demonstrate their feasibility as part of an effort to establish the organizational and technological foundation for development of photonic-crystal-based devices for commercial and military applications. Also known as photonic-band-gap devices, photonic crystals contain periodic structures having feature sizes in the submicron range — less than the wavelengths of light that the devices are intended to handle. Photonic crystals can be fabricated by techniques used in the integrated-circuit and microelectromechanical systems (MEMS) industries.

Posted in: Briefs, Photonics, Optics
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Infrared Data Link Using an MQW Modulator on a Retroreflector

A n infrared data link between a ground station and a small uninhabited helicopter in flight has been demonstrated in an effort to develop a type of system for free-space optical communication between (1) a larger and relatively stationary platform, and (2) a smaller and relatively mobile platform. In a system of this type, rather than using laser transmitters with their associated gimbaled telescopes and pointing/tracking subsystems on both platforms, one uses only a single such laser transmitter on the larger platform (in this case, the ground station). The single laser transmitter is capable of tracking the smaller platform (in this case, the helicopter) and transmitting data to the smaller platform in the conventional way via modulation of the outgoing laser beam. The field of view of the receiver on the smaller platform is wide enough to capture the laser beam, without need for a large receiving telescope and its aiming subsystem. For transmitting data from the smaller to the larger platform, a large fraction of the laser power incident on the smaller platform is modulated and retroreflected to the larger platform, by means of an InGaAs-based multiple-quantum-well (MQW) light modulator on a cornercube retroreflector (see Figure 1).

Posted in: Briefs, Photonics, Data exchange, Optics, Rotary-wing aircraft
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Development Packages for M-Modules and PMCs

MEN Micro, Inc. (Ambler, PA) introduced the Universal Submodule (USM) development packages for M-Modules and PMCs that turn specialized I/O requirements into a series of standard products. The product implements a board’s desired functionality through one or more IP cores in an FPGA, augmenting the flexibility of M-Modules and PMCs with individual functionality. The same USM may be used on M-Modules, PMC modules, XMCs, and conduction- cooled PMC modules. Operating temperature is -40 to 85°C.

Posted in: Products, Products, Electronics & Computers
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Analog Output Boards

United Electronics Industries (UEI, Canton, MA) has released the DNA-AO-308 series of analog output boards for PowerDNA DAQ Cubes. Each board has eight analog output channels with maximum update rates to 100 kHz per channel (800 kHz per board).

Posted in: Products, Products, Electronics & Computers
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Single-Board Computers

Aitech Defense Systems, Inc. (Chatsworth, CA) has expanded the C900 series of rugged 3U CompactPCI (cPCI) single-board computers (SBCs) with the C903, available in air- or conduction-cooled models; both conform to PICMG 2.0 R3.0 and ANSI/VITA 30.1-1991 specifications, respectively.

Posted in: Products, Products, Electronics & Computers
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