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- 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
This thesis explores the implications that the outcome of a certain U.S. lawsuit involving antiquities could have on practices and programs in the United States, related to cultural heritage and history. This paper examines the Rubin et al case, which sought to attach a collection of ancient Persian artifacts (known as The Persepolis Tablets) as a source of legal compensation. Presented as a case study, and using primary and secondary research sources, this paper analyzes the Rubin et al lawsuit and the factors that led to its initiation, and seeks to determine how and why adverse consequences could result from its final ruling. This thesis demonstrates that the final decision in the lawsuit could leave a negative impact on a number of practices related to cultural heritage in the United States, especially with regards to cultural and academic institutions such as museums and universities.
ContributorsAhouraiyan, Taraneh (Author) / Warren-Findley, Jannelle (Thesis advisor) / Warrren-Findley, Jannelle (Committee member) / Thompson, Victoria (Committee member) / Smith, Louis (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
Art museums are institutions with a mission to not only preserve art and culture for the public, but to provide visitors with an educational experience. This qualitative case study includes three art museums in the Phoenix Metropolitan Area: a university art museum, a large public museum in Downtown Phoenix, and a contemporary art museum in the city of Scottsdale. This research study sought to identify the ways in which eight art museum employees from the education and administration departments identify their institutions as educational. Data was collected and analyzed through the methods of direct observations and field notes, one-on-one interviews, and photographs of educational programming.
After examining these art museums and conducting eight interviews, a description of each observation is displayed using examples of photographs and field notes. Although findings suggest a variety of educational programs for a range of visitors in each institution, all three museums offered comparable programs, activities, and events. This research study revealed similar ideas, themes, and perspectives between art museum educators and administrators. Findings indicate the importance of collaboration between both museum departments in order to ensure the success of their museums. All eight participants in the study had a passion for art and art museums as well as visitor education. Additionally, participants had concurrent thoughts in their interviews regarding concepts of educational programming, cultural diversity approaches, art museum fundamental roles, and overall educational goals.
After examining these art museums and conducting eight interviews, a description of each observation is displayed using examples of photographs and field notes. Although findings suggest a variety of educational programs for a range of visitors in each institution, all three museums offered comparable programs, activities, and events. This research study revealed similar ideas, themes, and perspectives between art museum educators and administrators. Findings indicate the importance of collaboration between both museum departments in order to ensure the success of their museums. All eight participants in the study had a passion for art and art museums as well as visitor education. Additionally, participants had concurrent thoughts in their interviews regarding concepts of educational programming, cultural diversity approaches, art museum fundamental roles, and overall educational goals.
ContributorsLechner, Nicole (Author) / Young, Bernard (Thesis advisor) / Stokrocki, Mary (Committee member) / Watts, Jamie (Committee member) / Arizona State University (Publisher)
Created2018
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
Description
In this thesis, I examine the inclusion of American Indians as museum subjects and participants in Charles Willson Peale's Philadelphia Museum. To determine the forces that informed Peale's curatorship, I analyze Peale's experiences, personal views on education and scientific influences, specifically Carl Linnaeus, George-Louis Leclerc, Comte de Buffon and Thomas Jefferson. Peale created a polarized natural history narrative divided between Anglo-Americans and races that existed in a “natural state.” Within the museum's historical narrative, Peale presented Native individuals as either hostile enemies of the state or enlightened peacekeepers who accepted the supremacy of Americans. Peale's embrace of Native visitors demonstrated a mixture of racial tolerance and belief in racial hierarchy that also characterized democratic pedagogy. I derive the results by examining Peale's correspondence, diaries and public addresses, as well as administrative documents from the museum such as accession records, guidebooks, lectures and museum labels. I conclude that although Peale believed his museum succeeded in promoting tolerance and harmony among all cultures, his message nevertheless promoted prejudice through the exaltation of “civilized men.” By studying the social and intellectual constraints under which Peale operated, it is possible to see the extent to which observation of and commentary on ethnic and racial groups existed in America's earliest public culture and shaped early American museum history. Contemporary museums strive for cultural preservation and tolerance, therefore analysis of Peale's intentions and effects may increase the self-awareness of today's museum professionals.
ContributorsKeller, Laura (Author) / O'Donnell, Catherine (Thesis advisor) / Toon, Richard (Thesis advisor) / Osburn, Katherine (Committee member) / Arizona State University (Publisher)
Created2015
Description
Many contemporary artists have turned to the past in order to negotiate and make sense of their relationship with the present. Similarly, museums have begun to look back in order to push forward and through a revisionist lens they scrutinize their collections and reveal ignored object histories. A prominent method some museums implement is allowing contemporary artists to comb through the vaults and present new relationships between their objects to their visitors. Through a psychological analysis of memory, and theorists’ dissection of nostalgia, object agency, and contemporaneity, I argue that artists Spencer Finch, Do Ho Suh, Newsha Tavakolian, Solmaz Daryani, Malekeh Nayiny, Mitra Tabrizian, Mark Dion, Fred Wilson, and Gala Porras-Kim function as revivalists – or artists whose works use memory and nostalgia to bring the past back to life. By attempting to retrieve memories, create nostalgic experiences, and question histories, they make their works tools for remembrance, reconciliation, and renegotiation with the past and present. The concerns these artists bring to the surface through their works build an understanding of how memory and nostalgia function as devices for personal meaning-making, trauma processing, and human-object relationship building.
ContributorsZiesmann, Hannah Grace (Author) / Fahlman, Betsy (Thesis advisor) / Codell, Julie (Committee member) / Lineberry, Heather (Committee member) / Arizona State University (Publisher)
Created2020