Matching Items (7)
Filtering by
- Genre: Masters Thesis
- Creators: Arizona State University
- Creators: Chakraborty, Bijeta
- Creators: Peterson, Cory
- Member of: ASU Electronic Theses and Dissertations
Description
Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased efficiency, but at the cost of distortion. Class AB amplifiers have low efficiency, but high linearity. By modulating the supply voltage of a Class AB amplifier to make a Class H amplifier, the efficiency can increase while still maintaining the Class AB level of linearity. A 92dB Power Supply Rejection Ratio (PSRR) Class AB amplifier and a Class H amplifier were designed in a 0.24um process for portable audio applications. Using a multiphase buck converter increased the efficiency of the Class H amplifier while still maintaining a fast response time to respond to audio frequencies. The Class H amplifier had an efficiency above the Class AB amplifier by 5-7% from 5-30mW of output power without affecting the total harmonic distortion (THD) at the design specifications. The Class H amplifier design met all design specifications and showed performance comparable to the designed Class AB amplifier across 1kHz-20kHz and 0.01mW-30mW. The Class H design was able to output 30mW into 16Ohms without any increase in THD. This design shows that Class H amplifiers merit more research into their potential for increasing efficiency of audio amplifiers and that even simple designs can give significant increases in efficiency without compromising linearity.
ContributorsPeterson, Cory (Author) / Bakkaloglu, Bertan (Thesis advisor) / Barnaby, Hugh (Committee member) / Kiaei, Sayfe (Committee member) / Arizona State University (Publisher)
Created2013
Description
From inception, the earliest museums in Europe were a haven for artifacts, many of which represented world cultures within its walls. The tradition of encyclopedic collecting characterized European museums and U.S. institutions modeled themselves after this example. In the 20th century, defining cultural property, in the form of excavated objects, became a priority for many nations and resulted in the scrutiny of ancient artifacts, in particular. This led to the establishment of international protocols which sought to protect items during times of both peace and war. Despite international legislation, the trade of illicit antiquities continued. A major advocate for repatriation, the nation of Italy aggressively sought return of many objects from antiquity and recently approached the Metropolitan Museum of Art regarding several items whose provenance was suspect. Ultimately the conflict was resolved through The Metropolitan Museum of Art-Republic of Italy Agreement of February 21, 2006, which transferred the title of six antiquities to Italy in return for long term loans of equivalent objects to the museum. The landmark agreement represents a mutually profitable resolution to a situation potentially plaguing thousands of institutions worldwide. The implications of replication of the agreement can potentially change how museums, nations and the public understand concepts of ownership and may reduce the role of permanent collections in favor of sharing, rather than possessing, world heritage.
ContributorsFeller, Andrea (Author) / Serwint, Nancy (Thesis advisor) / Sweeney, J. Gray (Committee member) / Sealy Lineberry, Heather (Committee member) / Arizona State University (Publisher)
Created2011
Description
The Victorian era was the age of museum development in the United States. In the wake of these institutions, another important figure of the nineteenth century emerged--the flâneur. The flâneur represents the city, and provided new mechanisms of seeing to the public. The flâneur taught citizens how to gaze with a panoptic eye. The increasing importance of cultural institutions contributed to a new means of presenting power and interacting with the viewing public. Tony Bennett's exhibitionary complex theory, argues that nineteenth-century museums were institutions of power that educated, civilized, and through surveillance, encourage self-regulation of crowds. The flâneur's presence in the nineteenth century informed the public about modes of seeing and self-regulation--which in turn helped establish Bennett's theory inside the museum. The popular writing and literature of the time provides an opportunity to examine the extent of the exhibitionary complex and the flâneur. One of the most prominent nineteenth-century authors, Henry James, not only utilizes museums in his work, but he often uses them in just the manner Bennett puts forth in his theory. This is significant because the ideas about museums in James's work shaped the minds of an expanding literary public in the United States, and further educated, civilized, and regulated readers. James also represents the flâneur in his writing, which speaks to broader cultural implications of the both exhibitionary complex on the outside world, and the effects of broader cultural influences on the museum. Beyond the impact of James's work, in the late nineteenth century American culture increasingly became centered around the printed word. The central position of books in American culture at the end of the nineteenth century allowed books and libraries to appropriate the exhibitionary complex and become tools of power in their own right. The book and the library relate to the museum as part of a larger cultural environment, which emerged as a result of modernity and a response to the ever-changing nineteenth-century world.
ContributorsHarrison, Leah Gibbons (Author) / Szuter, Christine (Thesis advisor) / Warren-Findley, Jannelle (Committee member) / Toon, Richard (Committee member) / Arizona State University (Publisher)
Created2011
Description
Class D Amplifiers are widely used in portable systems such as mobile phones to achieve high efficiency. The demands of portable electronics for low power consumption to extend battery life and reduce heat dissipation mandate efficient, high-performance audio amplifiers. The high efficiency of Class D amplifiers (CDAs) makes them particularly attractive for portable applications. The Digital class D amplifier is an interesting solution to increase the efficiency of embedded systems. However, this solution is not good enough in terms of PWM stage linearity and power supply rejection. An efficient control is needed to correct the error sources in order to get a high fidelity sound quality in the whole audio range of frequencies. A fundamental analysis on various error sources due to non idealities in the power stage have been discussed here with key focus on Power supply perturbations driving the Power stage of a Class D Audio Amplifier. Two types of closed loop Digital Class D architecture for PSRR improvement have been proposed and modeled. Double sided uniform sampling modulation has been used. One of the architecture uses feedback around the power stage and the second architecture uses feedback into digital domain. Simulation & experimental results confirm that the closed loop PSRR & PS-IMD improve by around 30-40 dB and 25 dB respectively.
ContributorsChakraborty, Bijeta (Author) / Bakkaloglu, Bertan (Thesis advisor) / Garrity, Douglas (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
Description
ABSTRACT
Millions of US aging individuals are at risk for mild cognitive impairment (MCI), the early stage of Alzheimer's disease (Ad). Ad is progressive; there is no clinical cure to date. Certain drugs treat symptoms yet fog memory. Memory activity is critical to strengthen cognition. The Phoenix Art Museum (PAM) and Banner Alzheimer's Institute (BAI) founded the Arts Engagement Program (AEP), a non-clinical, specialized arts program for adults with (MCI) and their caregiver. The museum environment is thought to enhance communication and raise self-esteem in certain MCI individuals. The interior surroundings may spurn memory enhancement. Scholarship to substantiate this theory is minimal; therefore, further studies are required. Empirical literature regarding design elements researched specific types of memory impairment was employed. The hypotheses that design elements of the museum's infrastructure and design elements from art themes enhance memory, and the results of these findings when applied to other environments enhance memory emerged. An experience-based study was performed. Semi-structured interviews noting design elements of both infrastructure and art were conducted after each of nine AEP sessions with volunteers from 8 dyads, a term used by the PAM as one caregiver and one MCI individual. The presiding docent was later interviewed. Volunteer interviews with dyads and docents was coded and ranked. Overlapping themes that tallied five or higher were considered significant due the low sample size. Results showed that neither group considered infrastructure design elements or art theme design elements a contributor to memory enhancement. The hypotheses proved null. Both groups expressed pleasure in experiencing the PAM’s environment. Keywords: MCI, infrastructure, art themes.
Millions of US aging individuals are at risk for mild cognitive impairment (MCI), the early stage of Alzheimer's disease (Ad). Ad is progressive; there is no clinical cure to date. Certain drugs treat symptoms yet fog memory. Memory activity is critical to strengthen cognition. The Phoenix Art Museum (PAM) and Banner Alzheimer's Institute (BAI) founded the Arts Engagement Program (AEP), a non-clinical, specialized arts program for adults with (MCI) and their caregiver. The museum environment is thought to enhance communication and raise self-esteem in certain MCI individuals. The interior surroundings may spurn memory enhancement. Scholarship to substantiate this theory is minimal; therefore, further studies are required. Empirical literature regarding design elements researched specific types of memory impairment was employed. The hypotheses that design elements of the museum's infrastructure and design elements from art themes enhance memory, and the results of these findings when applied to other environments enhance memory emerged. An experience-based study was performed. Semi-structured interviews noting design elements of both infrastructure and art were conducted after each of nine AEP sessions with volunteers from 8 dyads, a term used by the PAM as one caregiver and one MCI individual. The presiding docent was later interviewed. Volunteer interviews with dyads and docents was coded and ranked. Overlapping themes that tallied five or higher were considered significant due the low sample size. Results showed that neither group considered infrastructure design elements or art theme design elements a contributor to memory enhancement. The hypotheses proved null. Both groups expressed pleasure in experiencing the PAM’s environment. Keywords: MCI, infrastructure, art themes.
ContributorsHill, Carol (Author) / Shraiky, James (Thesis advisor) / Takamura, John (Committee member) / Stein, Morris (Committee member) / Arizona State University (Publisher)
Created2015
Description
In this thesis, a digital input class D audio amplifier system which has the ability
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
ContributorsBai, Jing (Author) / Bakkaloglu, Bertan (Thesis advisor) / Arizona State University (Publisher)
Created2015
Description
The research titled “A Comparative Analysis of Museums in Paris, Barcelona,
and Phoenix” critically reviews six museums in three culturally diverse countries. This research looks at features within marketing, space, and branding which may or may not differ depending on socio-cultural factors, histories, traditions, etc. in Spain, France, and the United States. A conclusion is formed around the identity of each museum through the variables of marketing, space, and branding.
and Phoenix” critically reviews six museums in three culturally diverse countries. This research looks at features within marketing, space, and branding which may or may not differ depending on socio-cultural factors, histories, traditions, etc. in Spain, France, and the United States. A conclusion is formed around the identity of each museum through the variables of marketing, space, and branding.
ContributorsWeiler, Libby A (Author) / Bernardi, Jose (Thesis advisor) / Fehler, Michelle (Committee member) / Harmon-Vaughan, Beth (Committee member) / Arizona State University (Publisher)
Created2016