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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
This study examines the relations among three aspects of temperament (shyness, impulsivity, and effortful control), resting respiratory sinus arrhythmia (RSA) recorded during a calming film and RSA suppression during three behavioral measures of effortful control, and adjustment (anxiety and externalizing behavior) in a sample of 101 preschool-age children. Principal components analysis was used to create composites for effortful control, shyness, impulsivity, anxiety, and externalizing behavior, and hierarchical regression analysis was used to test the study hypotheses. As expected, baseline RSA was negatively related to effortful control in shy children, but was unrelated to effortful control in children who were not shy. It was hypothesized that high baseline RSA would reduce the relation between shyness and anxiety, and between impulsivity and externalizing behavior; this hypothesis was supported for externalizing behavior, but not for anxiety. The interaction between impulsivity and RSA as a predictor of externalizing was statistically independent of effortful control, indicating that these are unique effects. Finally, it was hypothesized that RSA suppression would be positively related to effortful control for children low, but not high, in shyness. There was a marginal interaction between shyness and RSA suppression, with RSA suppression marginally negatively related to EC for children low in shyness, but unrelated to effortful control for children high in shyness; the direction of this association was opposite predictions. These findings indicate that RSA is more strongly related to effortful control for children high in shyness, and that it consequently may not be appropriate to use RSA as an index of EC for all children. This study also draws attention to the need to consider the context in which baseline RSA is measured because a true baseline may not be obtained for shy children if RSA is measured in an unfamiliar laboratory context. The finding that high RSA moderated (but did not eliminate) the relation between impulsivity and externalizing behavior is consistent with the conceptualization of RSA as a measure of self-regulation, but further research is needed to clarify the mechanism underlying this effect.
ContributorsSulik, Michael John (Author) / Eisenberg, Nancy (Thesis advisor) / Spinrad, Tracy L. (Committee member) / Lemery-Chalfant, Kathryn (Committee member) / Arizona State University (Publisher)
Created2012
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
The moderating effects of five characteristics of peers--their effortful control, anger, sadness, aggression, and positive peer behavior--were investigated in two separate series of analyses of preschooler's social behavior: (a) the relation between children's own effortful control and social behavior, and (b) the relation between children's shyness and reticent behavior. Latent variable interactions were conducted in a structural equation framework. Peer context anger and effortful control, albeit with unexpected results, interacted with children's own characteristics to predict their behavior in both the EC and shy model series; these were the only significant interactions obtained for the EC model series. The relation between shyness and reticent behavior, however, showed the greatest impact of peer context and, conversely, the greatest susceptibility to environmental variations; significant interactions were obtained in all five models, despite the limited range of peer context sadness and aggression observed in this study.
ContributorsHuerta, Snježana (Author) / Eisenberg, Nancy (Thesis advisor) / Spinrad, Tracy (Committee member) / Pina, Armando (Committee member) / Geiser, Christian (Committee member) / Arizona State University (Publisher)
Created2012
Description
The purpose of this study was to examine whether dispositional sadness predicted children's prosocial behavior, and whether empathy-related responding (i.e., sympathy, personal distress) mediated this relation. It was hypothesized that children who were dispositionally sad, but well-regulated (i.e., moderate to high in effortful control), would experience sympathy versus personal distress, and thus would engage in more prosocial behaviors than children who were not well-regulated. Constructs were measured across three time points, when children were 18-, 30-, and 42-months old. In addition, early effortful control (at 18 months) was investigated as a potential moderator of the relation between dispositional sadness and empathy-related responding. Separate path models were computed for sadness predicting prosocial behavior with (1) sympathy and (2) personal distress as the mediator. In path analysis, sadness was found to be a positive predictor of sympathy across time. There was not a significant mediated effect of sympathy on the relation between sadness and prosocial behavior (both reported and observed). In path models with personal distress, sadness was not a significant predictor of personal distress, and personal distress was not a significant predictor of prosocial behavior (therefore, mediation analyses were not pursued). The moderated effect of effortful control was significant for the relation between 18-month sadness and 30-month sympathy; contrary to expectation, sadness was a significant, positive predictor of sympathy only for children who had average and low levels of effortful control (children high in effortful control were high in sympathy regardless of level of sadness). There was no significant moderated effect of effortful control on the path from sadness to personal distress. Findings are discussed in terms of the role of sadness in empathy-related responding and prosocial behavior as well as the dual role of effortful control and sadness in predicting empathy-related responding.
ContributorsEdwards, Alison (Author) / Eisenberg, Nancy (Thesis advisor) / Spinrad, Tracy (Committee member) / Reiser, Mark R. (Committee member) / Arizona State University (Publisher)
Created2012
Description
This longitudinal study examined the relations between self-regulation and reading achievement from kindergarten through second grade. In addition to the broader concept of effortful control, this study looked at various sub-components, including attention focusing and inhibitory control. A series of unconditional latent growth curve models were estimated to assess the initial level and growth of children’s parent- and teacher-reported effortful control and reading skills. In addition, parallel-process latent-growth curve models were estimated to examine the relations between the growth parameters (e.g., how the initial level and growth in self-regulation relates to the initial level and growth in reading). Parent-reported inhibitory control and effortful control displayed linear growth over this time period. Teacher-reported self-regulation did not change significantly. Reading achievement increased across all three time points, but the rate of growth was steeper from kindergarten through first grade than from first to second grade. Results from the parallel-process models showed that the kindergarten scores for parent-reported attention focusing and inhibitory control were negatively related to growth in Letter Word abilities from first through second grade, whereas initial teacher-reported attention focusing, inhibitory control, and effortful control were negatively related to growth in Passage Comprehension abilities from first to second grade. This study illustrates important relations between self-regulation and reading abilities throughout the first few years of elementary school.
ContributorsWall, Carla (Author) / Valiente, Carlos (Thesis advisor) / Jahromi, Laudan (Committee member) / Thompson, Marilyn (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 relations between aspects of social understanding (e.g., theory of mind, ToM, and emotion understanding, EU) were studied in relation to language and effortful control (EC). Data were collected when children were 30, 42, and 54 months of age (N's = 216, 192, and 168 for T1, T2, and T3, respectively). Children were assessed via mother and caregiver reports, and through observational measures. Although language and ToM did not relate within time, there was limited support for early language positively predicting later ToM. Language and EU were positively related within time, and there was some support for early language positively predicting later EU. Unexpectedly, significant positive relations were found for early EU predicting later language. ToM and EC were positively related within T3, and there was some support for early EC predicting later ToM. EU and EC were often positively related within time. Early EU also tended to positively predict later EC, whereas the opposite relation was not found. There was no support for significant a significant relation between EU and ToM. Findings suggest that children's early language may lead to later EC, and that early EU may help promote later EC and language; thus, it is important for parents and teachers to promote these early skills.
ContributorsKong, Tiffany (Author) / Eisenberg, Nancy (Thesis advisor) / Caterino, Linda (Thesis advisor) / Spinrad, Tracy (Committee member) / Arizona State University (Publisher)
Created2011
Description
Background: Premature infants may be at risk for lower effortful control, and subsequent lower academic achievement, peer competence, and emotional and physical wellness throughout the lifespan. However, because prematurity is related to obstetrical and neonatal complications, it is unclear what may drive the effect. Effortful control also has a strong heritable component; therefore, environmental factors during pregnancy and the neonatal period may interact with genetic factors to predict effortful control development. In this study, I aimed to dissect the influences of genetics, prematurity, and neonatal and obstetrical complications on the development of effortful control from 12 months to 10 years using a twin cohort. Methods: This study used data from the Arizona Twin Project, an ongoing longitudinal study of approximately 350 pairs of twins. Twins were primarily Hispanic/Latinx (23.8%-27.1%) and non-Hispanic/Latinx White (53.2%-57.8%), and families ranged in socioeconomic status with around one-third falling below or near the poverty line. Of the twins, 62.6% were born prematurely. Effortful control was assessed via parent report at six waves. Results: There was not a significant relationship between gestational age and effortful control regardless of whether obstetrical and neonatal complications were controlled for. Biometric twin modeling revealed that the attentional focusing subdomain of effortful control was highly heritable. Gestational age did not moderate genetic and environmental estimates. Conclusions: The findings help inform the risk assessment of prematurity and provide evidence for differing etiology of each subdomain of effortful control and the strong role of genetics in effortful control development.
ContributorsPickett, Janna (Author) / Lemery-Chalfant, Kathryn (Thesis advisor) / Su, Jinni (Committee member) / Eggum, Natalie D (Committee member) / Arizona State University (Publisher)
Created2023
Description
Research on self-regulatory variables like mindfulness and effortful control proposes strong links with physical and mental health outcomes across the lifespan, from childhood and adolescence to adulthood and old age. One pathway by which self-regulation may confer health benefits is through individual differences in reports of and emotional responses to daily negative and positive events. Mindfulness is broadly defined as non-reactivity to inner experiences, while effortful control is broadly defined as attentional and behavioral regulation. Mindfulness and effortful control have both been conceptualized to exert their beneficial effects on development through their influence on exposure/engagement and emotional reactivity/responsiveness to both negative and positive events, yet few empirical studies have tested this claim using daily-diary designs, a research methodology that permits for examining this process. With a sample of community-dwelling adults (n=191), this thesis examined whether dispositional mindfulness (i.e., non-reactivity of inner experience) and effortful control (i.e., attention and behavioral regulation) modulate reports of and affective reactivity/responsiveness to daily negative and positive events across 30 days. Results showed that mindfulness and effortful control were each associated with reduced exposure to daily stressors but not positive events. They also showed that mindfulness and effortful control, respectively, predicted smaller decreases in negative affect and smaller increases in positive affect on days that positive events occurred. Overall, these findings offer insight into how these self-regulatory factors operate in the context of middle-aged adults’ everyday life.
ContributorsCastro, Saul (Author) / Infurna, Frank (Thesis advisor) / Doane, Leah (Committee member) / Davis, Mary (Committee member) / Arizona State University (Publisher)
Created2018