Measurements, Models, Systems and Design

531 s.

NASA Space Engineering Research Center Symposium on VLSI Design

The NASA Space Engineering Research Center (SERC) is proud to offer, at its second symposium on VLSI design, presentations by an outstanding set of individuals from national laboratories and the electronics industry. These featured speakers share insights into next generation advances that will serve as a basis for future VLSI design. Questions of reliability in the space environment along with new directions in CAD and design are addressed by the featured speakers

Design and characterization of downconversion mixers and the on-chip calibration techniques for monolithic direct conversion radio receivers

This thesis consists of eight publications and an overview of the research topic, which is also a summary of the work. The research described in this thesis is focused on the design of downconversion mixers and direct conversion radio receivers for UTRA/FDD WCDMA and GSM standards. The main interest of the work is in the 1-3 GHz frequency range and in the Silicon and Silicon-Germanium BiCMOS technologies. The RF front-end, and especially the mixer, limits the performance of direct conversion architecture. The most stringent problems are involved in the second-order distortion in mixers to which special attention has been given. The work introduces calibration techniques to overcome these problems. Some design considerations for front-end radio receivers are also given through a mixer-centric approach. The work summarizes the design of several downconversion mixers. Three of the implemented mixers are integrated as the downconversion stages of larger direct conversion receiver chips. One is realized together with the LNA as an RF front-end. Also, some stand-alone structures have been characterized. Two of the mixers that are integrated together with whole analog receivers include calibration structures to improve the second-order intermodulation rejection. A theoretical mismatch analysis of the second-order distortion in the mixers is also presented in this thesis. It gives a comprehensive illustration of the second-order distortion in mixers. It also gives the relationships between the dc-offsets and high IIP2. In addition, circuit and layout techniques to improve the LO-to-RF isolation are discussed. The presented work provides insight into how the mixer immunity against the second-order distortion can be improved. The implemented calibration structures show promising performance. On the basis of these results, several methods of detecting the distortion on-chip and the possibilities of integrating the automatic on-chip calibration procedures to produce a repeatable and well-predictable receiver IIP2 are presented.reviewe

Sensor Signal and Information Processing II

In the current age of information explosion, newly invented technological sensors and software are now tightly integrated with our everyday lives. Many sensor processing algorithms have incorporated some forms of computational intelligence as part of their core framework in problem solving. These algorithms have the capacity to generalize and discover knowledge for themselves and learn new information whenever unseen data are captured. The primary aim of sensor processing is to develop techniques to interpret, understand, and act on information contained in the data. The interest of this book is in developing intelligent signal processing in order to pave the way for smart sensors. This involves mathematical advancement of nonlinear signal processing theory and its applications that extend far beyond traditional techniques. It bridges the boundary between theory and application, developing novel theoretically inspired methodologies targeting both longstanding and emergent signal processing applications. The topic ranges from phishing detection to integration of terrestrial laser scanning, and from fault diagnosis to bio-inspiring filtering. The book will appeal to established practitioners, along with researchers and students in the emerging field of smart sensors processing

Engineering Education and Research Using MATLAB

MATLAB is a software package used primarily in the field of engineering for signal processing, numerical data analysis, modeling, programming, simulation, and computer graphic visualization. In the last few years, it has become widely accepted as an efficient tool, and, therefore, its use has significantly increased in scientific communities and academic institutions. This book consists of 20 chapters presenting research works using MATLAB tools. Chapters include techniques for programming and developing Graphical User Interfaces (GUIs), dynamic systems, electric machines, signal and image processing, power electronics, mixed signal circuits, genetic programming, digital watermarking, control systems, time-series regression modeling, and artificial neural networks

On-Chip Analog Circuit Design Using Built-In Self-Test and an Integrated Multi-Dimensional Optimization Platform

Nowadays, the rapid development of system-on-chip (SoC) market introduces tremendous complexity into the integrated circuit (IC) design. Meanwhile, the IC fabrication process is scaling down to allow higher density of integration but makes the chips more sensitive to the process-voltage-temperature (PVT) variations. A successful IC product not only imposes great pressure on the IC designers, who have to handle wider variations and enforce more design margins, but also challenges the test procedure, leading to more check points and longer test time. To relax the designers’ burden and reduce the cost of testing, it is valuable to make the IC chips able to test and tune itself to some extent. In this dissertation, a fully integrated in-situ design validation and optimization (VO) hardware for analog circuits is proposed. It implements in-situ built-in self-test (BIST) techniques for analog circuits. Based on the data collected from BIST, the error between the measured and the desired performance of the target circuit is evaluated using a cost function. A digital multi-dimensional optimization engine is implemented to adaptively adjust the analog circuit parameters, seeking the minimum value of the cost function and achieving the desired performance. To verify this concept, study cases of a 2nd/4th active-RC band-pass filter (BPF) and a 2nd order Gm-C BPF, as well as all BIST and optimization blocks, are adopted on-chip. Apart from the VO system, several improved BIST techniques are also proposed in this dissertation. A single-tone sinusoidal waveform generator based on a finite-impulse-response (FIR) architecture, which utilizes an optimization algorithm to enhance its spur free dynamic range (SFDR), is proposed. It achieves an SFDR of 59 to 70 dBc from 150 to 850 MHz after the optimization procedure. A low-distortion current-steering two-tone sinusoidal signal synthesizer based on a mixing-FIR architecture is also proposed. The two-tone synthesizer extends the FIR architecture to two stages and implements an up-conversion mixer to generate the two tones, achieving better than -68 dBc IM3 below 480 MHz LO frequency without calibration. Moreover, an on-chip RF receiver linearity BIST methodology for continuous and discrete-time hybrid baseband chain is proposed. The proposed receiver chain implements a charge-domain FIR filter to notch the two excitation signals but expose the third order intermodulation (IM3) tones. It simplifies the linearity measurement procedure–using a power detector is enough to analyze the receiver’s linearity. Finally, a low cost fully digital built-in analog tester for linear-time-invariant (LTI) analog blocks is proposed. It adopts a time-to-digital converter (TDC) to measure the delays corresponded to a ramp excitation signal and is able to estimate the pole or zero locations of a low-pass LTI system

MEASUREMENT AND ANALYSIS OF SEA WAVES NEAR A REFLECTIVE STRUCTURE

Merged with duplicate record 10026.1/2047 on 06.20.2017 by CS (TIS)Methods and equipment for the measurement of ocean waves were reviewed and their suitability assessed for the aim of this project: field measurement of sea waves near a reflective coastal structure such as a breakwater. None was found to be suitable. The functional and performance objectives are set out for a new system. The evolution of the final design, based on an array of pressure sensors, is described. The whole system is intended to be deployed on the sea-bed. It is fully self contained and independent of shore based services. Located away from the surf zone it is well placed to survive storm conditions and unauthorised interference. Theoretical methods for the re-construction of surface elevation records from measured sub-surface pressures, and the experimental findings of other workers, are presented. Available methods of estimating the wave directional spectrum from a spatial array of surface elevation records are reviewed, and the most appropriate one implemented. The system has given extensive service at a number of coastal defence sites. The results of subsequent analysis of selected data sets are presented in detail. They show the pronounced nodal structure in amplitude expected in the presence of wave reflection, clearly demonstrating that a single point measurement is likely to give misleading estimates of incident wave height. For near-calm to moderate, shore-normal incident wave conditions the results were found to agree with theoretical predictions both of wave height as a function of distance offshore, and of the structure's frequency-dependent reflection coefficient. For rougher conditions, in which both theoretical and physical models are less applicable, the results agreed with visual observations

The identification of structural modal parameters, as an alternative in-vivo diagnosis for osteoporosis

Includes bibliographies.An alternative non-invasive diagnostic technique was sought for the diagnosis of osteoporosis in human subjects. The tibia vibration technique was proposed after reviewing the literature on detection techniques for osteoporosis. The basis of diagnosis of the tibia vibration technique is the measured resonant frequency of the patient's tibia. The patient's tibia is excited, generally by means of an impact hammer, while the response is captured and resonant frequencies extracted. This dissertation does not attempt to measure the resonant frequencies of a human tibia, but rather develop and validate the required experimental protocol and system identification procedures, on a simple test structure. A theoretical finite element model of the test structure was developed to ensure that both the experimental protocol and system identification procedures provided accurate results. The impulse response technique was adopted to excite the test structure