Matching Items (11)
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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
Intimate couple relationships are integral to the lives of most adults, and a typical stepping-stone in beginning a family. Thus, it is imperative to understand personal and interpersonal factors associated with healthy, long-lasting relationships (e.g., relationship satisfaction). One factor that may promote healthy relationships is mindfulness. Mindfulness has been linked to positive physical and psychological outcomes (see Kabat-Zinn, Lipworth, & Burney; Carmody & Baer, 2008), but has been minimally studied in the context of couple relationships. Research has also identified the corrosive effect of hostile communication cues on relationships (Gottman, 1994). The current study examined associations between mindfulness, corrosive communication cues, and relationship satisfaction in the context of cohabiting couples using actor-partner interdependence models (APIM; Kenny, Kashy, and Cook, 2006). Self-report questionnaires assessed five aspects of mindfulness: observing, describing, awareness, non-judgment of inner experience, and non-reactivity to inner experience. Women's non-judgment of inner experience, one of five mindfulness facets, was positively associated with the women's own relationship satisfaction. Other facets of mindfulness were not significantly associated with relationship variables. These findings and considerations for future research are discussed.
ContributorsFord, Annalise (Author) / Shapiro, Alyson (Thesis advisor) / Iida, Masumi (Thesis advisor) / Christopher, F (Committee member) / Arizona State University (Publisher)
Created2014
Description
ABSTRACT
This study examines the ways in which employees experience moral emotions that violate employee treatment and how employees co-construct moral emotions and subsequent expressions of dissent. This qualitative study consisted of 123 full-time employees and utilized open-coding, content analysis, constant comparison analysis, and concept mapping. The analysis revealed that employees expressed dissent laterally as a series of sensemaking processes, such as validation of feelings, moral assessments, and assessing the fear of moral transgressions. Employees also expressed dissent as a series of risk assessments that overlapped with the ways in which employees made sense of the perceived infraction. Employees' lateral dissent expression manifested as a form of social support which occasionally led to co-rumination. Employees expressed dissent upwardly when seeking a desired action or change. Circumvention was utilized as a direct reflection to the type and degree of moral transgression related to the person responsible for the mistreatment. Results indicated that experiencing moral emotions that led to expressing dissent with a designated audience was determined by where employees were situated in the cyclical model of communicating moral emotions and in relation to the co-construction of both the infraction related to employee mistreatment and the experience of moral emotions. Results contribute to the existing body of literature on dissent and emotions. A discussion synthesizing the findings and analysis is presented, in addition to the implications for future research.
KEYWORDS: Emotion, Dissent, Moral Emotions, Sensemaking, Risk-Assessment, Social Support, Co-Rumination
This study examines the ways in which employees experience moral emotions that violate employee treatment and how employees co-construct moral emotions and subsequent expressions of dissent. This qualitative study consisted of 123 full-time employees and utilized open-coding, content analysis, constant comparison analysis, and concept mapping. The analysis revealed that employees expressed dissent laterally as a series of sensemaking processes, such as validation of feelings, moral assessments, and assessing the fear of moral transgressions. Employees also expressed dissent as a series of risk assessments that overlapped with the ways in which employees made sense of the perceived infraction. Employees' lateral dissent expression manifested as a form of social support which occasionally led to co-rumination. Employees expressed dissent upwardly when seeking a desired action or change. Circumvention was utilized as a direct reflection to the type and degree of moral transgression related to the person responsible for the mistreatment. Results indicated that experiencing moral emotions that led to expressing dissent with a designated audience was determined by where employees were situated in the cyclical model of communicating moral emotions and in relation to the co-construction of both the infraction related to employee mistreatment and the experience of moral emotions. Results contribute to the existing body of literature on dissent and emotions. A discussion synthesizing the findings and analysis is presented, in addition to the implications for future research.
KEYWORDS: Emotion, Dissent, Moral Emotions, Sensemaking, Risk-Assessment, Social Support, Co-Rumination
ContributorsKamrath, Jessica K (Author) / Kassing, Jeffrey W. (Thesis advisor) / Waldron, Vincent R. (Committee member) / Meân, Lindsey J. (Committee member) / Arizona State University (Publisher)
Created2015
Description
The current study is the first qualitative investigation aimed solely at understanding what it means to communicate conditional forgiveness in serious romantic relationships. Conditional forgiveness is forgiveness that has been offered with the stipulation that the errant behavior cease. It is a provocative topic because some argue genuine forgiveness is not conditional, but recent discoveries that have associated its use with severe transgressions and relational deterioration suggest it is a critical site for investigation. This inductive analysis of open-ended data from 201 anonymous surveys identified both distinctions between and intersections of conditional forgiveness, forgiveness, and reconciliation. A relational dialectics analysis also revealed that reconcilable-irreconcilable was the overarching tension for conditional forgivers and six additional tensions also were also discovered: individual identity-couple identity, safety-risk, certainty-uncertainty, mercy-justice, heart-mind, and expression-suppression. Of particular intrigue, the current analysis supports the previous discovery of implicit conditional forgiveness--suppressing conditions, sometimes in response to physical and substance abuse. Ultimately, the current analysis contributes to the enduring conversation aimed at understanding the communication and pursuit of forgiveness and reconciliation. It addresses one of the basic instincts and paradoxes of existing with others--the balance between vulnerability and protection.
ContributorsKloeber, Dayna Noel (Author) / Waldron, Vincent R. (Thesis advisor) / Kelley, Douglas L. (Committee member) / Kassing, Jeffrey W. (Committee member) / Fisher, Carla L. (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
Prior research looking at procedural justice has largely focused on legal authorities, such as the police. There is a gap in the research regarding the influence of procedurally-just treatment of other criminal justice professionals, including 911 operators. These individuals are often the first contact citizens have when initiating police services, and it is likely that 911 operators set the stage for how police encounters with the public unfold. Using a factorial vignette design, this study tests the causal links between procedural injustice and several outcome measures, including cooperation, satisfaction, callback likelihood, and willingness to testify in court. Data from a university-based sample (n=488) were used to estimate a series of ordinal regression models. The results show that participants who received the injustice stimuli were generally less likely to report they would call 911 in the future, cooperate with the 911 operator if asked additional questions, cooperate with the police once they arrived on the scene, and had lower levels of satisfaction with the how the operator handled the call. These results were significant across two different scenarios (i.e., breaking and entering and traffic accident). Seriousness of the encounter also varied across these outcomes, but the magnitude of the effect was more modest. The results demonstrate the effect non-sworn personnel, such as 911 operators, can have on the outcome of police-citizen encounters.
ContributorsFlippin, Michaela R (Author) / Reisig, Michael D. (Thesis advisor) / Young, Jacob T.N. (Committee member) / Trinkner, Rick (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 purpose of this study was to examine the contributions of language anxiety, acculturation and social connectedness with American people to the counseling self-efficacy of international counseling students (ICSs) in the United States. The study used hierarchical multiple regression analysis with a sample of ICSs from counseling, counseling psychology and related programs in the U.S. (N=72). Major findings indicated that ICSs’ language anxiety was inversely associated with their counseling self-efficacy; neither ICSs’ acculturation nor social connectedness with American people had a significant relationship with counseling self-efficacy. Further, there was no significant interaction between language anxiety and social connectedness with American people; language anxiety, acculturation, social connectedness with American people, and the interaction between language anxiety and social connectedness with American people together did not account for a significantly different amount of variance in counseling self-efficacy over and above the variance accounted for by language anxiety alone. Implications, limitations and recommendations for future research are discussed.
ContributorsLi, Chi, M.C (Author) / Bernstein, Bianca L (Thesis advisor) / Homer, Judith Ann (Committee member) / Spanierman, Lisa Beth (Committee member) / Arizona State University (Publisher)
Created2016
Description
Proponents of cues-filtered-out approaches to communication suggest that the quality of person-to-person interaction is diminished when that interaction is mediated by technology. This postulation has implications for communication given the surging popularity of text messaging in the United States. It is important to examine the degree to which text messaging may inhibit successful communication due to the detriments of technologically mediated communication. The relation between text messaging and romantic relationship satisfaction in individuals ages 18-45 was investigated because successful communication is widely known by researchers and lay individuals to be an integral aspect of healthy intimate relationships. The Relationship Assessment Scale (RAS) (Hendricks, 1988) and an inventory of text messaging behavior was administered to graduate students (n = 22), undergraduate students (n = 24), and people not affiliated with universities (n = 104). Using responses on these inventories, whether or not (1) frequency of text messaging and (2) preference for a particular method of communication are related to romantic relationship satisfaction were evaluated. It was hypothesized that (1) a higher frequency of text messaging will be inversely related with romantic relationship satisfaction and (2) that a participant indicating a preference for verbal phone communication over text messaging communication will be positively correlated with romantic relationship satisfaction. The lack of statistically significant results prevented the drawing of conclusions about relationships between text messaging frequency or preference for voice communication over texting and romantic relationship satisfaction.
ContributorsOkonowsky, Lindsay (Author) / Tracey, Terence (Thesis advisor) / Robinson-Kurpius, Sharon (Committee member) / Tran, Giac-Thao (Committee member) / Arizona State University (Publisher)
Created2016
Description
Stress in romantic relationships is an all-too-common phenomenon that has detrimental effects on relationship well-being. Specifically, stress can increase partners’ negative interactions, ultimately decreasing effective communication and overall relationship functioning. Positive dyadic coping (DC) occurs when one partner assists the other in coping with stress (e.g. empathizing or helping the partner problem-solve solutions to their stress), and has been proposed as a method of buffering the deleterious effect of stress on interaction quality. One possible mechanism between the positive associations between DC and interaction quality could be how partners verbally express their support (e.g., more we-talk) during discussions about external stress. Using real-time interaction data from 40 heterosexual couples, this project examined whether observed positive and negative DC was associated with greater (or lesser) levels of perceived interaction quality. Further, language use (i.e., pronouns, emotion words, cognition words) was assessed as mediators in the associations between DC and interaction quality. Overall, results suggested that language did not mediate the effect of DC on interaction quality; however, there were several interesting links between DC, language, and interaction quality. Implications of these findings for relationship researchers and mental health clinicians working with couples are discussed.
ContributorsLau, Kin Hang (Author) / Randall, Ashley K. (Thesis advisor) / Duran, Nicholas (Committee member) / Pereira, Jennifer (Committee member) / Arizona State University (Publisher)
Created2017