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Photon-Counting Chirped Amplitude Modulation Ladar

This work is a follow-on to an effort to develop a method using Geiger-mode avalanche photodiode (GM-APD) photon-counting detectors in the U.S. Army Research Laboratory’s chirped amplitude modulation (AM) ladar receiver to yield sensitivities approaching the shot noise limit. Such sensitivities represent about four orders of magnitude improvement over the sensitivities of the currently used unity-gain, optoelectronic mixing (OEM) metal-semiconductor-metal (MSM) detectors. A variant of the chirped AM ladar has been experimentally assembled and tested, and new single photon-counting detector products were evaluated in terms of their benefits to the chirped AM ladar.

Posted in: Briefs, Photonics, Measurements, Radar, Semiconductor devices, Product development, Military vehicles and equipment
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Measurement of Transient Heat Flux and Surface Temperature Using Embedded Temperature Sensors

A report describes approximate solutions for surface temperature and heat flux for two embedded temperature sensors. The solutions were verified and the range of validity was established using several methods including comparisons with an exact analytical solution for a linear problem and a numerical calculation for a non-linear problem.

Posted in: Briefs, Physical Sciences, Mathematical models, Sensors and actuators, Thermal testing
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Considerations of Aeroacoustics in Turbojet-Engine Testing

A study of the aeroacoustics of a turbojet-engine test cell has been performed as one step in the development of a computational aeroacoustics capability (CAA) that could provide guidance for the design and operation of such cells. Ground testing of turbojet engines in test cells necessarily involves very high acoustic amplitudes, often severe enough to cause damage to test-cell equipment and to engines under test. Heretofore, the acoustic responses of test cells containing energetic jets have been poorly understood and generally unpredictable. The CAA capability is intended to enable prediction of deleterious acoustic events, making it possible to design test cells and choose operating conditions to prevent damage and thereby avoid the costly interruption of test schedules.

Posted in: Briefs, Physical Sciences, Acoustics, Turbojet engines, Performance tests, Aerodynamics
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Imaging and Spectral Measurements of Explosions

A document describes experiments performed to investigate rates of delivery of energy onto targets from different explosive formulations. The experiments were designed to measure relative positions of blast fireballs and leading shock fronts; determine whether different explosive formulations exhibit unique spectral signatures; determine temperatures of gases and solids near fireball surfaces; and measure rates of heating as functions of time. In the experiments, unconfined explosions were observed using time-resolved laser shadowgraphy, spectrometry integrated over the first 50 ms following initiation, time-resolved three-wavelength pyrometry, and time-resolved heat-flux measurements.

Posted in: Briefs, Physical Sciences, Measurements, Imaging, Fire, Impact tests, Thermal testing
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Patient Monitoring Using Capacitive Sensors

Capacitive sensors can be used to measure many different physical parameters that are important when monitoring the health of patients. In particular, the technical advances made by sensor manufacturers in using micro electro mechanical systems (MEMS), fabricated using silicon microchip manufacturing techniques, have opened up new possibilities for integration which improve the ease and adaptability of their use.

Posted in: Articles, Articles, Electronics & Computers, Microelectricmechanical device, Sensors and actuators, Medical equipment and supplies, Silicon alloys
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Designing Flexible Printed Circuit Boards

General purpose flexible circuit boards are those with electronic components that can be bent to fit in tight spaces. Most are just one or two layers thick and are meant for "flex to install" applications, as they will tolerate limited flex cycles. Circuit boards like this are often found in a variety of medical and consumer products.

Posted in: Articles, Articles, Electronics & Computers, Integrated circuits, Fabrication
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Software Development for Low Power Designs

The increasing emphasis on green technologies has focused more attention on low power design. Microcontroller vendors are responding by increasing their offerings of ultra low power devices that consume as little as 350 uA/MHz and have sub-uA sleep modes.

Posted in: Articles, Articles, Electronics & Computers, Computer software / hardware, Power electronics, Sustainable development, Energy consumption
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New Small Form Factor Storage Standard Targets Embedded Systems

To achieve small size, low power consumption and fast time to market requirements, embedded systems designers often look to chipsets found in cell phone handsets or mobile internet devices (MIDs) to cost-effectively meet their design requirements. These components, whether they are off-the-shelf chipsets from Intel, AMD or Freescale, or FPGA's from Xilinx, Altera, or Actel, that later migrate to custom ASICS, often define the available storage interfaces. These chipsets are widely understood and supported and more often than not, make use of USB, SD, MMC or some other type of serial programmable interface that is not usually defined with traditional storage such as PATA or SATA.

Posted in: Application Briefs, Application Briefs, Electronics & Computers, Embedded software, Integrated circuits, Data management
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Audio Enrichment Technology

ARC International (San Jose, CA), has introduced the Virtual Bass™ audio enrichment technology that delivers a deep rich bass response on existing speakers or headphones, eliminating the need to add subwoofers or other audio components. Virtual Bass optimizes a product's bass rendering capabilities, taking into account the analog to digital converter, amplifier, speaker cavity, and speaker driver, resulting in audio that more accurately reflects the original performance without adding artificial signals or muffling voice articulation and audio clarity.

The low-power ARC® Sound Subsystem is a 100-hour audio playback solution for portable devices. When implemented on the ARC® Sound Subsystem, Virtual Bass offers a complete solution that lowers manufacturing cost while producing an enhanced listening experience. The complete solution includes an underlying silicon solution that cuts chip size and lowers power consumption, a complete set of software to provide playback of any digital music format, all the tools needed to develop the chip solution, and the complete Sonic Focus™ audio enrichment technology suite.

For Free Info Click Here.

Posted in: Products, Products, Electronics & Computers
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DSP Library

STMicroelectronics (Geneva, Switzerland) has released a new DSP library for its ARM Cortex-M3-based STM32 microcontrollers. The STM32 DSP library is license-free, royalty-free, and provides a large number of valuable functions coded in C or assembly language. These include a PID controller, Fourier transform functions, and a selection of digital filters such as 16-bit FIR, IIR direct-form, and IIR canonical-form filters. The functions are ready to use, easy to integrate, and are comprehensively documented to promote software maintainability and accelerate endproduct development. Operations such as multiply-accumulate or hardware divide can be executed within only two cycles. Demonstrations running on the STM32F103 Performance Line MCU have performed a complex 256-point 16-bit radix-4 Fast Fourier Transform (FFT) in only 362μs. Compared to alternative hybrid architectures such as digital signal controllers (DSC) with separate control- and signal-processing cores, the STM32 streamlines software development, enhances performance, and allows developers to use standard tools. The new DSP libraries can be used with the IAR, Keil, and Raisonance tool-chains for the STM32. The DSP library reduces cost and time-to-market for applications such as digital power conversion, including solar-energy projects, closed-loop control of switched-mode power supplies, audio and speech processing, and digital image processing.

For Free Info Click Here.

Posted in: Products, Products, Electronics & Computers
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