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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
The subject of bilingual language use in the southwestern United States has been widely researched. However research pertaining to the Phoenix Metropolitan area is lacking. Studies have shown that language choice is governed by linguistic as well as social constraints (Gumperz, 1977; Poplack 1980; 1981). This study examined and compared the code-switching behaviors of two communities in the southwestern United States: Antonito, Colorado and the Phoenix Metropolitan area in Arizona. The study explored the social and linguistic factors that are said to govern code-switching behaviors such as the type of switches made (intra-sentential or single lexical switches), the position in the utterance where the switch occurs (final or other), the direction of the switch (an utterance beginning in English and ending in Spanish, or beginning in Spanish and ending in English), the gender and level of education of the participants (college or above; high school or below), the ethnicity of the interviewer (Anglo or Hispanic), as well as which of the aforementioned social and linguistic factors most favored intra-sentential switches. The study used corpus data, with four participants from each community for a total of eight interviews. Participants from each corpus were selected to control for gender, the highest level of education achieved and the ethnicity of the interviewer. The study found that in the corpora looked at, linguistic factors such as position of the switch and direction of the switch affected intra-sentential switches more than social factors, although in terms of frequencies within individual factor groups, social factors such as the ethnicity of the interviewer, and the participant's level of education were found to be significant in affecting code-switching behavior.
ContributorsCésar, Mariana (Author) / Cerron-Palomino, Alvaro (Thesis advisor) / Lafford, Barbara (Committee member) / García, Carmen (Committee member) / Arizona State University (Publisher)
Created2013
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
ABSTRACT This thesis analyzes the Spanish (SPA) and English (ENG) code-switching (CS) at Latino Vibe (LV), a bilingual radio station in Phoenix; Arizona from a sociolinguistic perspective. Using Gumperz's (1982) Conversational Functions of CS, Myers-Scotton's (1993) Markedness Model, and Bell's (1984) Audience Design model, this thesis intends to evaluate which one of these sociolinguistic models is the most accurate to explain the SPA-ENG CS at LV. In January 2009, the data were collected in a two week period of programming of the show "José y Tina en la mañana" (José and Tina in the morning), and then transcribed. This qualitative study consisted in analyzing the same subset of the data, corresponding to ten days. The model with the greater predictably of the types of CS and their causes would be considered the most appropriate for the data studied. The results show that CS is common and that codeswitched utterances are the most representative at LV. The conclusion also states that out of the three models, Gumperz's accounts better for the data than the other two. It explains more clearly the reasons why LV announcers code-switch in particular social contexts, and the important role of these switches during their interaction in this bilingual radio station. KEYWORDS: Code-switching, bilingual radio, Spanish-English
ContributorsBocanegra, Olga Lucía (Author) / Cerron-Palomino, Alvaro (Thesis advisor) / García, Carmen (Committee member) / Lafford, Barbara (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
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
Code-switching, a bilingual language phenomenon, which may be defined as the concurrent use of two or more languages by fluent speakers is frequently misunderstood and stigmatized. Given that the majority of the world's population is bilingual rather than monolingual, the study of code-switching provides a fundamental window into human cognition and the systematic structural outcomes of language contact. Intra-sentential code-switching is said to systematically occur, constrained by the lexicons of each respective language. In order to access information about the acceptability of certain switches, linguists often elicit grammaticality judgments from bilingual informants. In current linguistic research, grammaticality judgment tasks are often scrutinized on account of the lack of stability of responses to individual sentences. Although this claim is largely motivated by research on monolingual strings under a variety of variable conditions, the stability of code-switched grammaticality judgment data given by bilingual informants has yet to be systematically investigated. By comparing grammaticality judgment data from 3 groups of German-English bilinguals, Group A (N=50), Group B (N=34), and Group C (N=40), this thesis investigates the stability of grammaticality judgments in code-switching over time, as well as a potential difference in judgments between judgment data for spoken and written code-switching stimuli. Using a web-based survey, informants were asked to give ratings of each code-switched token. The results were computed and findings from a correlated groups t test attest to the stability of code-switched judgment data over time with a p value of .271 and to the validity of the methodologies currently in place. Furthermore, results from the study also indicated that no statistically significant difference was found between spoken and written judgment data as computed with an independent groups t test resulting in a p value of .186, contributing a valuable fact to the body of data collection practices in research in bilingualism. Results from this study indicate that there are significant differences attributable to language dominance for specific token types, which were calculated using an ANOVA test. However, when using group composite scores of all tokens, the ANOVA measure returned a non-significant score of .234, suggesting that bilinguals with differing language dominances rank in a similar manner. The findings from this study hope to help clarify current practices in code-switching research.
ContributorsGrabowski, Jane (Author) / Gilfillan, Daniel (Thesis advisor) / Macswan, Jeff (Thesis advisor) / Ghanem, Carla (Committee member) / Arizona State University (Publisher)
Created2011