DSpace community: Engineering

Design of RSD-cyclic and hybrid RSD-Cyclic/sigma-delta ADCs

Tue, 10 Jul 2007 22:58:59 GMT

title: Design of RSD-cyclic and hybrid RSD-Cyclic/sigma-delta ADCs authors: Atris, Youssef H.
abstract: In this research work two contributions to the area of analog to digital data converters have been discussed. The area of focus is the RSD-Cyclic and sigma-delta ADC. First a novel hybrid RSD-Cyclic-sigma-delta architecture is introduced which is a combination of the RSDCyclic ADC and sigma-delta ADC architectures. The resolution obtained with this hybrid architecture is n = n1 + n2 , where n1 = MSBrsd stands for the most significant bits obtained from the RSD-architecture and n2 = LSBsdl stands for the least significant bits obtained from the sigma-delta architecture. Since the sigma-delta block is required to achieve only an n2-bit resolution (n2, n1 < n ) the over-sampling ratio required for the sigma-delta is not as high as the over-sampling ratio required to achieve n-bit resolution. Also the requirements on the RSD-Cyclic block are only the requirements to achieve n1-bit resolution, which means that the requirements on the analog building blocks for the RSD-Cyclic part are more relaxed. Secondly, in the RSD-Cyclic area we have introduced a circuit technique that allows an entire ADC system to run on one operational amplifier without any loss of functionality. Therefore we will be saving power and area, both very desirable features for mobile applications.
description: Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering

Design of RSD-cyclic and hybrid RSD-Cyclic/sigma-delta ADCs

Tue, 10 Jul 2007 22:58:59 GMT

Statistic approach to static conductor thermal rating

Thu, 24 Apr 2008 22:58:59 GMT

title: Statistic approach to static conductor thermal rating authors: Shao, Miaolei; Jewell, Ward T.
abstract: This paper proposes applying the statistic analysis method for determination of static conductor thermal rating. The spectrum of the maximum current of conductor over a year is first calculated using Typical Meteorological Year (TMY2) data set as weather data and IEEE Standard 738-1993 as computation engine. The statistic analysis is then performed to calculate the cumulative distribution function (CDF) of the maximum current. Finally, the static conductor thermal rating can be determined based on the risk level which utilities are willing to take. The statistic analysis method helps system planners to determine the static conductor thermal rating by quantifying the risk of a conductor’s actual allowable maximum current higher than the static rating. This proposed method is applied to determine the static conductor thermal rating of different zones within Rocky Mountain and Desert Southwest area.
description: Paper presented to the 4th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Hughes Metropolitan Complex, Wichita State University, April 25, 2008.

Determination of carbon monoxide detector location in general aviation aircraft to improve safety

Thu, 24 Apr 2008 22:58:59 GMT

title: Determination of carbon monoxide detector location in general aviation aircraft to improve safety authors: Ahmady, Ali; Assadi, Morteza; Muthuswamy, Selvakumar
abstract: There are many sources of carbon monoxide (CO) leakage into the cabin of General Aviation (GA) aircraft. Exposure to CO, which is part of the engine exhaust in GA aircraft, can impede the pilot’s ability to direct the airplane which may lead to accidents. In order to prevent accidents, an electrochemical CO detector can be used to alert the pilot to the presence of CO. The objective of this study was to determine the best location for CO detector placement in GA aircraft. Early CO detection as well as visibility and accessibility of the detector were some of the parameters involved in determining the optimum CO detector location. Considering these issues, five detector placement locations were considered: visor, instrument panel, leg area of front seats (left and right sides), and rear seat. Field tests to monitor CO levels during GA flights were conducted at Kansas State University at Salina using data logging CO detectors. The results from these measurements have been categorized according to several different variables and then analyzed statistically. Measurements taken so far during the summer and early fall indicate that the majority of CO exposure events occurred on the ground before take-off. During such ground-based CO exposure events, the timing was consistent with open windows allowing exhaust fumes to enter the cockpit area. This paper will also discuss the results of additional measurements taken during the winter months when other modes of CO exposure may be involved.
description: Paper presented to the 4th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Hughes Metropolitan Complex, Wichita State University, April 25, 2008.