A design for testability study on a high performance automatic gain control circuit.

A comprehensive testability study on a commercial automatic gain control circuit is presented which aims to identify design for testability (DfT) modifications to both reduce production test cost and improve test quality. A fault simulation strategy based on layout extracted faults has been used to support the study. The paper proposes a number of DfT modifications at the layout, schematic and system levels together with testability. Guidelines that may well have generic applicability. Proposals for using the modifications to achieve partial self test are made and estimates of achieved fault coverage and quality levels presente

Analysis and application of digital spectral warping in analog and mixed-signal testing

Spectral warping is a digital signal processing transform which shifts the frequencies contained within a signal along the frequency axis. The Fourier transform coefficients of a warped signal correspond to frequency-domain 'samples' of the original signal which are unevenly spaced along the frequency axis. This property allows the technique to be efficiently used for DSP-based analog and mixed-signal testing. The analysis and application of spectral warping for test signal generation, response analysis, filter design, frequency response evaluation, etc. are discussed in this paper along with examples of the software and hardware implementation

Video guidance, landing, and imaging systems

The adaptive potential of video guidance technology for earth orbital and interplanetary missions was explored. The application of video acquisition, pointing, tracking, and navigation technology was considered to three primary missions: planetary landing, earth resources satellite, and spacecraft rendezvous and docking. It was found that an imaging system can be mechanized to provide a spacecraft or satellite with a considerable amount of adaptability with respect to its environment. It also provides a level of autonomy essential to many future missions and enhances their data gathering ability. The feasibility of an autonomous video guidance system capable of observing a planetary surface during terminal descent and selecting the most acceptable landing site was successfully demonstrated in the laboratory. The techniques developed for acquisition, pointing, and tracking show promise for recognizing and tracking coastlines, rivers, and other constituents of interest. Routines were written and checked for rendezvous, docking, and station-keeping functions

iPhone forensics methodology and tools

iPhone mobile devices are rapidly overtaking the new generation of mobile phones market, especially among the young generation. It is also gaining a lot of popularity among security specialists and fancy gadgets for collectors. The device is considered as a “special” mobile phone due to its ability to perform multi-operations if not multitasking. It can therefore be used as a entertainment media device, a camera, a GPS, Internet surfing via Wi-Fi technology, Internet Mobile Edge Services, personal organizer, and finally performing as a cell phone with all the usual services including sms, and so forth. However, the difference between the iPhone and the other conventional phones vendors is its ability to store and process huge volume of data which is supported by decent computing capabilities of the iPhone processor. As part of every technology, such a device can be used for legal and illegal activities. Therefore the potential risks from such “special” technology are not limited to the possibility of containing illegal materials, such as audios and visuals, including explicit materials, images, documents and the possibility of propagating malicious activities rapidly. Such modification can breach or tamper with the telecommunications network authorities and regulations. The goal of this paper is to focus on both the logical and the physical extraction of the iPhone generation one through the extraction of the iPhone flash drive NAND memory chip and also the logical extraction of data onto the second generation of iPhone using various techniques and methods at our disposal

Functional Verification of Power Electronic Systems

This project is the final work of the degree in Industrial Electronics and Automatic Engineering. It has global concepts of electronics but it focuses in power electronic systems. There is a need for reliable testing systems to ensure the good functionality of power electronic systems. The constant evolution of this products requires the development of new testing techniques. This project aims to develop a new testing system to accomplish the functional verification of a new power electronic system manufactured on a company that is in the power electronic sector . This test system consists on two test bed platforms, one to test the control part of the systems and the other one to test their functionality. A software to perform the test is also designed. Finally, the testing protocol is presented. This design is validated and then implemented on a buck converter and an inverter that are manufactured at the company. The results show that the test system is reliable and is capable of testing the functional verification of the two power electronic system successfully. In summary, this design can be introduced in the power electronic production process to test the two products ensuring their reliability in the market

A preliminary experiment definition for video landmark acquisition and tracking

Six scientific objectives/experiments were derived which consisted of agriculture/forestry/range resources, land use, geology/mineral resources, water resources, marine resources and environmental surveys. Computer calculations were then made of the spectral radiance signature of each of 25 candidate targets as seen by a satellite sensor system. An imaging system capable of recognizing, acquiring and tracking specific generic type surface features was defined. A preliminary experiment definition and design of a video Landmark Acquisition and Tracking system is given. This device will search a 10-mile swath while orbiting the earth, looking for land/water interfaces such as coastlines and rivers

FPGA ARCHITECTURE AND VERIFICATION OF BUILT IN SELF-TEST (BIST) FOR 32-BIT ADDER/SUBTRACTER USING DE0-NANO FPGA AND ANALOG DISCOVERY 2 HARDWARE

The integrated circuit (IC) is an integral part of everyday modern technology, and its application is very attractive to hardware and software design engineers because of its versatility, integration, power consumption, cost, and board area reduction. IC is available in various types such as Field Programming Gate Array (FPGA), Application Specific Integrated Circuit (ASIC), System on Chip (SoC) architecture, Digital Signal Processing (DSP), microcontrollers (μC), and many more. With technology demand focused on faster, low power consumption, efficient IC application, design engineers are facing tremendous challenges in developing and testing integrated circuits that guaranty functionality, high fault coverage, and reliability as the transistor technology is shrinking to the point where manufacturing defects of ICs are affecting yield which associates with the increased cost of the part. The competitive IC market is pressuring manufactures of ICs to develop and market IC in a relatively quick turnaround which in return requires design and verification engineers to develop an integrated self-test structure that would ensure fault-free and the quality product is delivered on the market. 70-80% of IC design is spent on verification and testing to ensure high quality and reliability for the enduser. To test complex and sophisticated IC designs, the verification engineers must produce laborious and costly test fixtures which affect the cost of the part on the competitive market. To avoid increasing the part cost due to yield and test time to the end-user and to keep up with the competitive market many IC design engineers are deviating from complex external test fixture approach and are focusing on integrating Built-in Self-Test (BIST) or Design for Test (DFT) techniques onto IC’s which would reduce time to market but still guarantee high coverage for the product. Understanding the BIST, the architecture, as well as the application of IC, must be understood before developing IC. The architecture of FPGA is elaborated in this paper followed by several BIST techniques and applications of those BIST relative to FPGA, SoC, analog to digital (ADC), or digital to analog converters (DAC) that are integrated on IC. Paper is concluded with verification of BIST for the 32-bit adder/subtracter designed in Quartus II software using the Analog Discovery 2 module as stimulus and DE0-NANO FPGA board for verification

Nanoscale Electrodes by Conducting Atomic Force Microscopy: Oxygen Reduction Kinetics at the Pt|CsHSO_4 Interface

We quantitatively characterized oxygen reduction kinetics at the nanoscale Pt|CsHSO_4 interface at ~150 °C in humidified air using conducting atomic force microscopy (AFM) in conjunction with AC impedance spectroscopy and cyclic voltammetry. From the impedance measurements, oxygen reduction at Pt|CsHSO_4 was found to comprise two processes, one displaying an exponential dependence on overpotential and the other only weakly dependent on overpotential. Both interfacial processes displayed near-ideal capacitive behavior, indicating a minimal distribution in the associated relaxation time. Such a feature is taken to be characteristic of a nanoscale interface in which spatial averaging effects are absent and, furthermore, allows for the rigorous separation of multiple processes that would otherwise be convoluted in measurements using conventional macroscale electrode geometries. The complete current-voltage characteristics of the Pt|CsHSO_4 interface were measured at various points across the electrolyte surface and reveal a variation of the oxygen reduction kinetics with position. The overpotential-activated process, which dominates at voltages below -1 V, was interpreted as a charge-transfer reaction. Analysis of six different sets of Pt|CsHSO_4 experiments, within the Butler-Volmer framework, yielded exchange coefficients (α) for charge transfer ranging from 0.1 to 0.6 and exchange currents (i_0) spanning 5 orders of magnitude. The observed counter-correlation between the exchange current and exchange coefficient indicates that the extent to which the activation barrier decreases under bias (as reflected in the value of α) depends on the initial magnitude of that barrier under open circuit conditions (as reflected in the value of i_0). The clear correlation across six independent sets of measurements further indicates the suitability of conducting AFM approaches for careful and comprehensive study of electrochemical reactions at electrolyte-metal-gas boundaries

Electrocatalysis in Solid Acid Fuel Cells

Solid state electrochemical reactions play a crucial role in many energy conversion devices, yet the pathways of many reactions remain unknown. The elusiveness of the reaction mechanisms is due, in part, to the complexity of electrochemical reactions; because electrochemical reactions require the interaction of many species (e.g., ions, electrons, and adsorbates) across multiple phases (e.g., electrolyte, catalyst, and gas phases), elucidation of the reaction pathway can quickly become complicated. In this work, we develop and utilize model catalyst | electrolyte systems, that is, structures of reduced complexity, to study electrode reactions in solid acid fuel cells which operate at intermediate temperatures of ~ 250 ºC. We employ AC impedance spectroscopy to explore the reaction pathway for hydrogen electro-oxidation over Pt thin films sputter-deposited atop the proton-conducting solid acid electrolyte CsH2PO4. We observed that hydrogen electro-oxidation occurs by diffusion of hydrogen through Pt, taking advantage of the entire Pt | CsH2PO4 interfacial area rather than being confined to the triple-phase sites. This insight opens up new avenues for developing high performance electrodes with low Pt loadings by eliminating the requirement that Pt-based electrodes be comprised of high triple-phase site densities long considered to be critical for Pt electrocatalysis. Indeed, even for flat, planar electrodes of very thin Pt films, we obtained a Pt utilization that is significantly higher than in typical composite electrodes. We also demonstrate the efficacy of a new tool for probing the spatial heterogeneity of electrochemical reactions at the metal | electrolyte interface. We characterized oxygen electro-reduction kinetics at the nanoscale Pt | CsHSO4 interface at ~ 150 ºC using conducting atomic force microscopy in conjunction with cyclic voltammetry and AC impedance spectroscopy. Not only did we find the electrochemical activity for oxygen electro-reduction to vary dramatically across the electrolyte surface but the current-voltage data, when analyzed in the Butler-Volmer framework, exhibited a strong counter-correlation between two key kinetic parameters, the exchange coefficient and exchange current. Specifically, the exchange current spanned five orders of magnitude while the exchange coefficient ranged between 0.1 and 0.6. Such a correlation has not been observed before and points to the power of atomic force microscopy for electrochemical characterization at electrolyte | metal | gas boundaries in general. As reduction in microstructural complexity is a key advantage in model electrode | electrolyte systems, we also sought to understand the bulk properties of solid acid compounds, specifically, the relationship between microstructure and the superprotonic phase transition, the latter of which lends solid acid compounds their high proton conductivities at intermediate temperatures. We found a correlation between phase transformation hysteresis and crystallographic compatibility of the high- and low-temperature phases of the Cs1–xRbxH2PO4 solid solution series. Therefore, it is to be expected that hysteresis, and therefore microcrack formation, can be minimized during phase transformation via the principle of crystallographic compatibility. This is confirmed in single crystals of CsHSO4, which was found to have higher crystallographic compatibility, lower hysteresis, and significantly fewer microcracks formed during phase transition compared to CsH2PO4. The apparent applicability of the theory of crystallographic compatibility implies a new tool for identifying solid acid compounds with suitable microstructures for fuel cell application and for model electrode | electrolyte systems. </p

A feasibility study of using Langley 0.3-m transonic cryogenic tunnel sidewall boundary-layer removal system for heavy gas testing

This report presents the results of a preliminary study for using the 0.3-m Transonic Cryogenic Tunnel sidewall boundary-layer removal system with heavy gas sulfur hexafluoride as the test medium. It is shown that the drive motor speed/power of the existing system and the additional heat load on the tunnel heat exchanger are the major problems limiting the boundary-layer removal system performance. Overcoming these problems can provide the capability to remove about 1.5 percent of the test section mass flow at Mach number M = 0.8 and about 5 percent at M = 0.25. Previous studies have shown that these boundary-layer mass flow removal rates can reduce the boundary-layer thickness by a factor of two at the model station. Also the effect of upstream boundary-layer removal on the airfoil test data is not likely to be significant under high lifting conditions. Near design conditions, corrections to the test Mach number may be necessary to account for sidewall boundary-layer effects