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- Genre: Masters Thesis
- Creators: Arizona State University
- Creators: Chakraborty, Bijeta
- 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
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
Prior sentencing research, especially research on cumulative disadvantage, has mainly focused on the treatment of male defendants, and little attention has been paid to female defendants, especially minority female defendants. Drawing on the intersectional vulnerability and focal concerns perspectives, the current study emphasizes the need to examine disparity in sentencing through an intersectional lens and across multiple decision-making points. Using the State Court Processing Statistics dataset (SCPS) from 1990-2009, this paper investigates the impact that race/ethnicity has for female defendants across individual and successive stages in the sentencing process. The results suggest that race operates through direct and indirect pathways to cause lengthier sentences for Black female defendants compared to White female defendants, thus providing evidence of cumulative disadvantage against Black female defendants. Theoretical, research, and policy implications will be discussed.
ContributorsKramer, Kelsey Layne (Author) / Wang, Xia (Thesis advisor) / Spohn, Cassia (Committee member) / Telep, Cody (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
Sociopolitical involvement has been previously shown to be associated with experiences of discrimination. Lesbian, gay, and bisexual (LGB) racial/ethnic minorities have faced multiple levels of discrimination from the mainstream community, racial/ethnic minority communities, and LGB communities. However, not many studies have investigated the association between intersectional forms of discrimination and sociopolitical involvement. The present study examines differences in perceptions of racism in the LGB community, sociopolitical involvement in racial/ethnic communities, and sociopolitical involvement in LGB communities among LGB racial/ethnic minorities (N = 203, MAge = 27.25). The sample included 107 (52.7%) men and 96 (47.3%) women; 41 (20.2%) lesbians, 89 (43.8%) gay men, and 73 (36.0%) bisexuals; 47 (23.2%) African Americans, 50 (24.6%) Asian Americans, 64 (31.5%) Latinos/as, and 42 (20.7%) from another race/ethnicity or mixed race. This study also looks at the association between perceptions of racism in the LGB community and sociopolitical involvement in racial/ethnic communities and/or LGB communities. Asian American participants reported perceiving higher levels of racism in the LGB community than Latino/a participants. No other differences in perceptions of racism in the LGB community were found between sexual orientation or by racial/ethnic group. No differences between racial/ethnic group or sexual orientations were found in sociopolitical involvement in racial/ethnic or LGB communities. When controlling for sexual orientation, gender, and race/ethnicity, perceptions of racism in the LGB community predicted sociopolitical involvement in racial/ethnic and LGB communities. By exploring correlates of discrimination from an intersectional perspective, this study provides a better understanding of the experiences of LGB racial/ethnic minorities.
ContributorsVanDaalen, Rachel (Author) / Santos, Carlos (Thesis advisor) / Homer, Judith (Committee member) / Tracey, Terence (Committee member) / Arizona State University (Publisher)
Created2016
Description
Through ideologies of gender identity, gender as performance, sexuality, and the transgressions thereof, this document serves as a memoir inside of a memoir. I made a pop concert dance piece through a western dance aesthetic with my thesis paper detailing the experience. What did that look like? Throughout this paper, I will explain my thought process, expectations, and experience through writing, which is a more challenging task for me. I am not an academic writer, but rather a rebel with a cause. My cause is to transgress the system in any way I’m able - through words, dance, and expression. As opposed to the artistic dance piece itself, this paper’s purpose is one of both selfish intent and catharsis. Given this, I approached my thesis paper with the same mindset used when developing my piece, in that I rebel fighting against the heteronormative standards that have run my life. I don’t fill this document with regurgitated theory. Moreover, this document morphed into a cathartic platform for me, a purging of counter-hegemonic principals and ideals.
ContributorsCruz, Felix (Author) / Fitzgerald, Mary (Thesis advisor) / Rex, Melissa (Committee member) / McMahon, Jeff (Committee member) / Arizona State University (Publisher)
Created2017
Description
How do Queer Black Women make sense of their experiences within educational settings? How do they engage in space-making? How do educational settings protect Black Queer Women's bodies? Through a series of in-depth interviews with individuals that identify as, are labeled by others as, or previously identified as Queer Black Women, I found that participants understood their lived experiences intersectionality and understood their experiences in educational settings as critical to their self-development. Participants described race, sexuality, and gender as overlapping systems of oppression that negatively affected their experiences within educational settings. Not only did participants experience discrimination due to their race or gender, but also due to their sexuality. This seen and/or invisible identity leads them to experience multiple axes of oppression, not only inflicted by peers and teachers, but also the institutions. The findings have implications for theories of intersectionality and queer of color critique.
ContributorsMelendez-Mayfield, Amina (Author) / Charron-Chenier, Raphael (Thesis advisor) / Lopez, Vera (Committee member) / Garcia, Rocio (Committee member) / Arizona State University (Publisher)
Created2022
Description
Black individuals and transgender and nonbinary (TNB) populations encounter daily microaggressions that negatively impact their mental health. Identity pride has been shown to moderate this association for Black and TNB populations separately. Unfortunately, research has not examined the impacts of simultaneously experiencing race-based and gender-based microaggressions in populations such as Black nonbinary individuals. Given this, there remains a significant gap in understanding the mental health impacts of racial and gender microaggressions and potential buffers for Black nonbinary individuals. The current study (N = 65) aimed to evaluate the association between intersectional microaggressions (IM) and depression and anxiety in Black nonbinary adults and the potential moderating effects of Black pride and nonbinary pride. A sample of Black nonbinary individuals was obtained from a larger longitudinal study with nonbinary adults. Hierarchical multiple regression analyses were run to examine the association between intersectional microaggressions and mental health outcomes and the interactions of Black pride and nonbinary pride. Results showed that intersectional microaggressions did not significantly predict depression or anxiety. Neither Black nor nonbinary pride were significant moderators of the association between IM and depression. For anxiety, results showed that Black pride was a significant moderator, such that those with higher levels of Black pride showed a stronger association between IM and anxiety. Further research is needed to investigate the impact of Black pride on anxiety and identify additional protective factors outside of pride for Black nonbinary individuals.
ContributorsHolman, Mel (Author) / Matsuno, Em (Thesis advisor) / Randall, Ashley (Committee member) / Capielo Rosario, Cristalís (Committee member) / Arizona State University (Publisher)
Created2023
Description
Sociopolitical involvement has been previously shown to be associated with experiences of discrimination. Lesbian, gay, and bisexual (LGB) racial/ethnic minorities have faced multiple levels of discrimination from the mainstream community, racial/ethnic minority communities, and LGB communities. However, not many studies have investigated the association between intersectional forms of discrimination and sociopolitical involvement. The present study examines differences in perceptions of racism in the LGB community, sociopolitical involvement in racial/ethnic communities, and sociopolitical involvement in LGB communities among LGB racial/ethnic minorities (N = 203, MAge = 27.25). The sample included 107 (52.7%) men and 96 (47.3%) women; 41 (20.2%) lesbians, 89 (43.8%) gay men, and 73 (36.0%) bisexuals; 47 (23.2%) African Americans, 50 (24.6%) Asian Americans, 64 (31.5%) Latinos/as, and 42 (20.7%) from another race/ethnicity or mixed race. This study also looks at the association between perceptions of racism in the LGB community and sociopolitical involvement in racial/ethnic communities and/or LGB communities. Asian American participants reported perceiving higher levels of racism in the LGB community than Latino/a participants. No other differences in perceptions of racism in the LGB community were found between sexual orientation or by racial/ethnic group. No differences between racial/ethnic group or sexual orientations were found in sociopolitical involvement in racial/ethnic or LGB communities. When controlling for sexual orientation, gender, and race/ethnicity, perceptions of racism in the LGB community predicted sociopolitical involvement in racial/ethnic and LGB communities. By exploring correlates of discrimination from an intersectional perspective, this study provides a better understanding of the experiences of LGB racial/ethnic minorities.
ContributorsVanDaalen, Rachel (Author) / Santos, Carlos (Thesis advisor) / Homer, Judith (Committee member) / Tracey, Terence (Committee member) / Arizona State University (Publisher)
Created2016
Description
This thesis examines the role of advocacy and social justice in the music of three living American women composers, and the ways their efforts as mentors, patrons, academics, and educators interact with their work as composers. Case studies include Gabriela Lena Frank (b. 1972), Missy Mazzoli (b. 1980), and Jennifer Jolley (b. 1981). My musicological narrative is informed by Kimberly Francis’s concept of women as “cultural mosaics” and Patricia Hill Collins’s theorization of intersectionality, which addresses the junction of variable characteristics (such as race, gender, or class) as they relate to an individual’s identity. I have centered my narrative on social issues these composers address through their activism and their music. Gabriela Lena Frank’s orchestral work, Peregrinos (2009), emphasizes Frank’s value of community outreach and her interdependence on others. Frank uses folklórica traditions and Latin mythology to musically recognize the diverse experiences of Latin American immigrants living in Indianapolis. Missy Mazzoli blends operatic traditions with electronics to convey messages of female empowerment in Song from the Uproar: The Lives and Deaths of Isabelle Eberhardt (2012). Mazzoli’s characterization of the fascinating life of this nineteenth-century woman resonates with modern understandings of intersectionality and agency, and aligns with her work with the Luna Composition Lab. Jennifer Jolley’s approach to musical activism in Prisoner of Conscience (2017) mirrors her philosophical and political messages explored on her blog and e-magazine articles. Juxtaposing punk rock with church motets and madrigals, Jolley comments on the nature of protest and the punishment of Russian feminist punk group, Pussy Riot.
I position these composers as cultural agents with diverse concerns and diverse means by which to voice them. Frank, Mazzoli, and Jolley each participate in valuable extra-musical roles outside of their compositions: from Gabriela Lena Frank’s Creative Academy of Music, to Mazzoli’s Luna Composition Lab, to Jolley’s NewMusicBox articles. Each of these composers negotiate agency within traditions that have not always been open to women, and they seek to further remedy race and gender inequities through their prominent positions as educators and composers.
ContributorsMartinac, Caitlin (Author) / Norton, Kay (Thesis advisor) / Saucier, Catherine (Committee member) / Hicks, Glen (Committee member) / Arizona State University (Publisher)
Created2021