Matching Items (6)
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
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
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
Research on cultural socialization, the process in which individuals learn messages regarding the traditions and values of their culture (Hughes et al., 2006), has dedicated little attention to Latinx and Asian American groups. This study examined whether an interdependent self-construal (i.e., viewing oneself as connected to others and endorsing behaviors that depend on others; Singelis, 1994) was a mediator between cultural socialization and ethnic identity for these two groups. The current study utilized mediation analyses to explore the associations between cultural socialization via different agents (i.e., parents, teachers, romantic partners, peers), interdependent self-construal, and ethnic identity exploration and commitment for Latinx (N = 258, 68.6% female, Mage = 20.54) and Asian (N = 281, 66.5% female, Mage = 20.34) American college-attending emerging adults. Results revealed that for the Latinx sample, interdependent self-construal mediated the relation between cultural socialization and ethnic identity exploration or commitment in regards to parents and peers, but not teachers. In addition, interdependent self-construal mediated the association between cultural socialization from romantic partners and ethnic identity commitment, but not exploration. For the Asian American sample, interdependent self-construal mediated the association between cultural socialization and ethnic identity exploration or commitment in regards to romantic partners and peers, but not parents and teachers. These results highlight the important role of different cultural socialization agents in ethnic identity formation for these two groups and suggest that the endorsement of cultural values can be a mechanism through which ethnic identity is strengthened.
ContributorsLam, Christina (Author) / Tran, Alisia (Giac-Thao) (Thesis advisor) / Santos, Carlos (Committee member) / Yoo, Hyung Chol (Brandon) (Committee member) / Arizona State University (Publisher)
Created2017
Description
My thesis, Asian American and dancing in Arizona; A reflection on the politics of choreographing migration and citizenship in a Red State is a written document that reflects on my creative process of making You don’t belong here, a site-specific, multimedia dance theater piece which I conceived, choreographed, and directed in partial fulfillment of my Master in Fine Arts in Dance degree (MFA) at Arizona State University (ASU) in Tempe, Arizona. I write this reflection from the corporeal perspective of my Asian body. My story comes from my cells that contain the memories of my ancestors, including the recent traumas of my parents that escaped war in China. I am writing from my feminist body, my fleshly archive. I am writing from a historically marginalized perspective. I write this reflection to provide my kinesthetic narrative for those that may not know that I exist at ASU. I consider the conservative political ethos of Arizona as an impetus to discover what it means to be Asian American and dancing in the desert.
ContributorsYoung, Angeline (Author) / Roses-Thema, Dr. Cynthia (Thesis advisor) / Dyer, Dr. Becky (Committee member) / Kwan, Dr. SanSan (Committee member) / Ping, Li-Chiao (Committee member) / Arizona State University (Publisher)
Created2017
Description
Using a sample of 309 Asian American college students, the present study examined the effects of color-blind racial ideology (i.e., unawareness of blatant racial issues, unawareness of racial privilege and unawareness of institutional racism) on the link between internalization of the model minority myth (i.e., unrestricted mobility and achievement orientation) and psychological distress (i.e., social climate stress, interracial stress, within group stress, racism stress and achievement stress). Results primarily suggest the denial of blatant racism and racial issues (and not denial of racial privilege and institutional racism) exacerbate the effect of internalizing the model minority myth related to unrestricted mobility, while it buffers the effect of internalizing the model minority myth related to achievement orientation on race-related social stress. Also, denial of racial privilege appears to buffer the effect of internalizing the model minority myth related to unrestricted mobility and within group stress. Clinical implications and future directions for research are discussed.
ContributorsParks, Sarah (Author) / Yoo, Hyung Chol (Thesis advisor) / Spanierman, Lisa (Committee member) / Giac-Thao Tran, Alisia (Committee member) / Arizona State University (Publisher)
Created2020