The design of a two-dimensional polarcardiograph and the use of two such two-dimensional devices to calculate the third polar coordinate together with the circuitry necessary to derive and amplify a set of voltages proportional to the Cartesian coordinates x, y, and z is described. Although the technique used for obtaining the polar coordinates is similar to that used in other instruments, the circuitry is somewhat different. This is dictated in part by the fact that this device is completely transistorized. Both the Frank and RAFE networks are available for the transformation from patient signals to a set of signals proportional to the Cartesian coordinates x, y, and z. Restoration of the base-line at the optimum time during the cardiac cycle is achieved through a system of gated feedback which is activated by a predictor circuit. The predictor is triggered by an automatic trigger selector. A threshold circuit is associated with each angle output in order to set the output to some predetermined value when the input signal level is so small as to make the angle output indeterminate. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis describes the simulation of a digital communication system on a digital computer. Delta modulation was chosen as the system, and its mode of action is first described. Several variations of the basic system are possible. In order to get the best transmission quality, a careful choice must be made of the system and of its design parameters. Conventional methods of finding these optimum parameters have difficulties which digital simulation can circumvent. The programming of the ALWAC III-E computer for this task is described. Difficulties were encountered due to the modest speed of the computer. The simulation experiments yielded many results of interest concerning the operation of both simple and complex delta modulation systems with different design parameters, and allowed an optimum system to be designed. Where it is possible to compare results with previous experimental work, the agreement is good. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

A critical discussion of various theories of cylindrical antennas is given* It is shown that the Hallen-King theory is of a semi-empirical nature. Both the current distribution and input impedance derived from this theory depend on a semi-empirical choice of an expansion parameter. It is also shown that the Hallen-King "slice generator" cannot be used to represent the effect of the transmission line. A theory which correctly accounts for this effect is developed and theoretical formulas are developed for both the current distribution and input impedance. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

A novel method for on-chip noise characterization of mm-wave circuits is presented. Different available methods for noise measurements and requirements for on-chip noise mea-surements are studied. The Y-factor method is chosen to be the more suitable method for in-situ applications since it does not require absolute measurements. A state of the art CMOS noise source is implemented in 32nm SOI CMOS technology to enable the in-situ noise measurements of a 20-35 GHz reconfigurable low noise amplifier. Measurement results show that the ENR of the noise source is repeatable enough so that the calibration of the noise source is only required for one integrated circuit. Using different scenarios for the noise figure response of the LNA, the performance of the noise source is evaluated. To the authors’ knowledge, this is the first time that an on-chip CMOS noise source is used for in-situ noise characterization of mm-wave frequency circuits.

An investigation into the stability of negative resistance-based source combining power amplifiers is conducted in this thesis. Two different negative resistance-based source combining topologies, a series and parallel version, are considered. Stability is analyzed using a simple and intuitive broadband approach that leverages linear circuit stability criterion and two different linearization methods: linearization around the operating point and in the frequency domain. Using this strategy, it is shown that conditions for self-sustained oscillation exist for both topologies. For the series combining topology, self-sustained oscillation is prevented by means of injection locking.

With an expected lifetime of 20 years and an expected cost of $500, the Cal Poly Sustainable Power for Electrical Resources (SuPER) project needed a strong central design. This thesis looks at the work completed by students over the previous 5 years, with an eye on the future, to create the phase 2 design. Part of this new structure focuses on a distributed communication bus for monitoring system health and status. Instead of complex and costly computer or FPGA systems, the new system will run solely with microcontrollers. This reduces costs and will hopefully still be used within 5, 10, and 20 years as the number of embedded devices continues to grow globally. The new system design was created using many systems engineering tools and benchmarks, including: requirements breakdown, hardware interfacing, software interfacing, safety, reliability, maintainability, and cost. Major components have been broken down into subsystems with well-defined requirements for implementation. These smaller projects can be completed by future team members as senior projects, independent work, or even Master’s theses. Upon test and integration, these subsystems will come together into a field-ready model to help bring power to the two billion people on Earth lacking it.

Graphene is an atomically thin two-dimensional (2-D) crystal with unique thermal, mechanical, and electronic transport properties such as the high mobility of carriers, perfect 2- D confinement and linear dispersion, etc., has been attracted many interest as a promising candidate for nano-scale devices over the past decades. Multilayer stacks of graphene and other stable, atomically thin, 2-D materials offer the prospect of creating a new class of heterostructure materials. Hexagonal boron- nitride (hBN), is a great candidate to be stacked with graphene due to an atomically 2-D layered structure with a lattice constant very similar to graphene (1.8% mismatch), large electrical band gap (∼4.7eV), and excellent thermal and chemical stability. The graphene/hBN based tunneling transistors show the resonant tunneling and strong negative differential resistance (NDR). These devices which have potential for future high-frequency and logic applications such as high-speed IC circuits, signal generators, data storage, etc., has been studied both theoretically and experimentally recently. The aim in this dissertation has been to study the effect of the uniaxial strain on the graphene nanoribbon resonant tunneling transistors (RTTs). The uniaxial strain may be induced either by an external stress applied to the graphene in a particular direction or by a substrate due to deposition of graphene on top of the other materials. The strain modifies distances between carbon atoms which leading to different hopping amplitudes among neighboring sites. A resonant tunneling transistor consisting of armchair graphene nanoribbon (AGNR) electrodes with three layers of hBN tunnel barrier between them has been considered. By using the nearest-neighbor tight-bind (TB) method and the nonequilibrium Green function (NEGF) formalism, the electronic transport characteristics of a RTT is calculated. In this work, we focus on how the strain affects the current-voltage characteristics of AGNR/hBN RTT.

Distance education has the ability to transcend distance and time, reaching students anywhere at any time, particularly those underrepresented in engineering. Engineering is a practice-oriented profession requiring an interweaving of scientific theory and applied hands-on activities. Despite the need for distance education in engineering, few studies have systematically investigated the impact of student achievement and attitude in distance engineering laboratories. This quasi-experimental research addressed that need by studying the cognitive and affective domains of achievement in engineering laboratories while employing computer-based and traditional oscilloscopes. The students from two courses, electrical engineering for nonmajors and electronic fundamentals, were randomly assigned into treatment and comparison groups. The students' achievement and attitudes were gauged using assessment instruments and an attitudinal survey. These results were statistically analyzed and conclusions are discussed. The results suggested that computer-based instruments were viable in engineering laboratories.

Constraint satisfaction and optimization techniques are commonly employed in scheduling problems, industrial manufacturing, and automation processes. Constraint Satisfaction Problem (CSP) also finds use in the design, synthesis, and optimization of embedded systems. In recent years online constraint solving techniques have been employed in embedded systems for dynamic system adaptation. In embedded systems, online constraint solving techniques are primarily used as on-board control software. Using CSP techniques for scheduling algorithms provides intelligent scheduling. This thesis discusses the architecture of an embedded, parallel finite-domain constraint solver for performing online constraint satisfaction. By modeling the scheduling problem as a CSP problem, the embedded system becomes adaptable to dynamic changes in the environment. The features of this solver are that it is implemented in a platform with multiple soft-core processors with distributed memory architecture. A tool is also developed that automates the partitioning of the given application and configures the underlying framework.

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