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Simulation Concept Exploits Tools for Computing Hybrids

The Simulation Concept – How to Exploit Tools for Computing Hybrids (SCHETCH) project is exploring the design modeling and simulation (M&S) process for developing advanced computing technology for future intelligent systems. The goal is to integrate new alternative computing concepts with existing silicon-based computing technology in hybrid computing architectures. A main premise behind this project is that, for an alternative-computing concept to move from the laboratory to a technology ready for the field, the proper M&S process must be in place. Adaptation and integration of commercially available software provides an opportunity to take advantage of existing functionality without investing time into developing new tools for new concepts. It was decided to focus on hardware concepts rather than software implementations, initially looking at three concepts: nanomechanical quantum computing, membrane computing, and deoxyribonucleic acid (DNA) computing.

Posted in: Briefs, Electronics & Computers, Computer simulation, Architecture, Computer software / hardware, Product development
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Asymmetric Core Computing for High-Performance Applications

High-performance computing (HPC) users have traditionally relied upon two things to supply them with processing power: speed of the central processing units (CPUs) and the scalability of the system. There are problems with this approach. Physical limitations are curtailing clock speed increases in general-purpose CPUs, the von Neumann load-execute-store approach does not map well to every computational problem, and systems of thousands of processors might be very inefficient, depending upon processor interconnection limitations.

Posted in: Briefs, Electronics & Computers, Architecture, Computer software / hardware, Integrated circuits
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Novel Wavelength Standards in the Near Infrared

The goal of this work was to develop a new class of portable optical frequency references based on sub-Doppler spectroscopy inside gas-filled, hollow-core photonic bandgap (PBG) optical fiber. The change in line width with core size, and narrower transitions inside a new “kagome” structured optical fiber, were demonstrated. A simplified and more compact method for observing saturated absorption spectroscopy in half-sealed photonic bandgap fibers, called the “reflected pump technique,” was realized. Two systems, each consisting of a narrow-line fiber laser locked to the P(13) transition in acetylene, were constructed. By comparing those two systems, it was possible to obtain stability data on the fiber-filled references.

A mode-locked Cr:forsterite laser was developed and stabilized to a GPS-disciplined Rb clock with which to characterize the gas-filled, hollow-fiber optical frequency references. It was found that these lasers offer noisier “f0” beats than Ti:sapphire lasers, but a method was found to dramatically reduce the f0 beat width. A study was initiated into the source of the noise and the exact explanation for the narrowing. In the meantime, absolute frequency measurements of the fiber laser locked to the hollow fiber references are in progress.

A generally useful technique was developed for splicing the photonic bandgap fibers to solid-core fibers using an arc fusion splicer, which makes PBG fibers easier to use in the laboratory. Toward making a completely sealed photonic bandgap fiber cell, PBG was spliced to solid-core fibers inside a vacuum system using a CO2 laser. Efforts to reproduce this in an acetylene vapor proved unsuccessful, most likely due to the thermal properties of acetylene.

This work was done by Kristan L. Corwin of Kansas State University for the Air Force Research Laboratory. For more information, download the Technical Support Package (free white paper) at www.defensetechbriefs.com/tsp under the Photonics category. AFRL-0132

Posted in: Briefs, Photonics, Fiber optics, Lasers, Spectroscopy
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Power Enhancement of a Rubidium Vapor Laser with a Master Oscillator Power Amplifier

The concept of alkali lasers was first suggested by Schalow and Townes in the late 1950s. In the 1970s, photo-dissociation of several of the alkali salts produced lasers with wavelengths ranging from the visible to the far infrared. Thirty years later, diode-pumped alkali lasers (DPAL) started rapidly gaining attention as highly efficient lasers as well as brightness converters. These systems partly owe their high efficiencies to the very small energy differences between the pump and lasing levels. Due to recent technological advances in the field of solid-state lasers, direct-diode pumping has provided the efficient, yet compact method for excitation.

Posted in: Briefs, Photonics, Amplifiers, Lasers, Thermal management
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Clock Oscillator

Crystek Crystals (Fort Myers, FL) has released the CCSO- 014-1090, a 1.090-GHz surface acoustic wave (SAW) clock oscillator that produces low-noise, low-jitter performance with true SineWave output, and -138 dBc/Hz phase noise at 10 kHz offset. It comes in a 14 PIN DIP hermetically sealed package, features a 12V input voltage, and generates a true sinewave with +12 dBm minimum output power. It has no sub-harmonic, and the second harmonic is -40 dBc max. Operating temperature is -55 °C to 105 °C.

Posted in: Products, RFM Catchall
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Gain Horn Antennas

The 600 Series standard gain horn antennas from Narda, an L-3 Communications company (Hauppauge, NY), are suitable for EMI and EMC testing applications covering waveguide bands from 2.6 to 40 GHz. Seven models cover 2.6 to 3.95 GHz, 3.95 to 5.86 GHz, 5.4 to 8.2 GHz, 8.2 to 12.4 GHz, 14 to 18 GHz, 18 to 26.5 GHz, and 26.5 to 40 GHz. Directivity patterns for all models include a beamwidth in the E and H planes from 23° at 40 GHz to 34° at 2.6 GHz. Weight ranges from 6 pounds for the 2.6 to 3.95 GHz model to 4.5 grams for the 18 to 40 GHz model. They are supported by waveguide-to-coax adapters from either Type-N female or SMA/3.5/2.9-mm female connectors.

Posted in: Products, RFM Catchall
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Microwave Power Sensors

Anritsu (Morgan Hill, CA) offers MA24108A/ MA24118A microwave USB power sensors that provide average power measurements from 10 MHz to 18 GHz over 60 dB of dynamic range. Employing a dual-path architecture, they can measure CW, multi-tone, and digitally modulated signals used in aero space/defense systems. They have built-in external trigger circuitry and an MCX connector interface to receive triggers from external stimuli. They also include a microcontroller, signal conditioning circuitry, ADC, and power supply.

Posted in: Products, RFM Catchall
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Compact Antennas

Antenna Factor (Merlin, OR) offers the HW Series 1⁄2-wave center-fed dipole antennas and 1⁄4-wave monopole antennas that attach using an FCC-compliant RP-SMA connector or standard SMA connector. The 1⁄2-wave dipoles are available in standard center frequencies of 868 and 916 MHz, while the 1⁄4-wave monopoles are available in 315, 418, and 433 MHz.

Posted in: Products, RFM Catchall
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Microwave Signal Generators

The 2500B series of microwave signal generators from Giga-tronics (San Ramon, CA) covers 100 kHz to 50 GHz with low phase noise, high rejection of harmonics, sub-harmonics, and spurious, high output power level. Six models cover 2.5, 8, 20, 26.5, 40, and 50 GHz. Accumulator High Frequency Feedback (AHFF™) technology delivers a switching speed of typically less than 500 μs for a 1 GHz step and as fast as 100 μs for small steps. Close to carrier phase noise is -90 dBc/Hz at 100 Hz. Generator noise performance is 10 kHz offset with a typical performance of -110 dBc/Hz. This series is suitable for radar and EW applications.

Posted in: Products, RFM Catchall
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Antenna Design Simulation

Magus (Stellenbosch, South Africa), in conjunction with FEKO (Hampton, VA), offers Antenna Magus, a design simulation software solution for antenna design and placement analysis. It offers a searchable collection of antennas, which can be explored to find, synthesize, and export antenna models. It can export synthesized antennas as FEKO models, which may then be refined, customized, analyzed, and optimized in FEKO. The software can also analyze electrically large structures, such as the MLFMM and hybrid asymptotic methods (MoM-PO, MoMGO, and MoM-UTD).

Posted in: Products, RFM Catchall
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