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Design of a low jitter digital PLL with low input frequencyJung, Seokmin 05 June 2012 (has links)
Complex digital circuits such as microprocessors typically require support circuitry that has traditionally been realized using analog or mixed-signal macros. PLL circuits are used in many integrated applications such as frequency synthesizers and inter-chip communication interfaces. As process technologies advance and grow in complexity, the challenge of maintaining required analog elements and performance for use in circuits such as PLLs grows. Recently, digital PLL (DPLL) has emerged as an alternative to analog PLL to overcome many constraints such as low supply voltage, poor analog transistor behavior, larger area due to integrated capacitor and process variability. However, DPLLs have high deterministic jitter due to quantization noise of time-to-digital converter (TDC) and digitally-controlled oscillator (DCO) and struggle with random jitter of oscillator.
In this thesis, hybrid analog/digital proportional/integral control is used to suppress TDC quantization error and digital phase accumulation techniques to mitigate DCO quantization error. VCO phase noise was reduced using an embedded voltage-mode feedback. This feedback loop is implemented by using a switched-C circuit which converts frequency to current. Designed in a 130nm CMOS process, the proposed DPLL generates more than 1GHz output frequency with low input frequency and achieves superior jitter performance compared to conventional DPLL in simulations. / Graduation date: 2013
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Acoustic Investigation of Production of Clusters by Saudi Second Language Learners of EnglishAlmalki, Hussain 28 March 2014 (has links)
Production errors made by second language (L2) learners of English have been attributed to markedness, L1 transfer or input frequency (cf. Major, 2001; Edwards & Zampini, 2008; Baptista, Rauber, & Watkins, 2009). This thesis examines the production of 17 English initial consonant clusters (e.g., /pr/ in “pray”) in a markedness relationship, whereby clusters with greater sonority distance between the first and second consonants are unmarked and clusters with smaller sonority distance between the first and second consonants are marked, by two groups of Saudi Arabian L2 English learners. It also explores the effect of input frequency and L1 transfer. Participants were asked to read 60 sentences and their reading was recorded for acoustic analysis. Analysis showed that “prothesis” was always used to simplify the clusters, and that, the duration of the prothetic vowel tended to get longer when clusters become more marked. Intermediate participants had greater degree of difficulty in producing the clusters and tended to insert a longer prothetic vowel in general. Markedness explained the performance on #sC clusters; however, performance on non #sC clusters was best explained by L1 transfer. Results further indicated that input frequency was irrelevant to this study.
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Aspects psycholinguistiques du développement du bilinguisme précoce : une étude de cas d'un enfant bilingue français-russe de 2 à 4 ans / Psycholinguistic aspects of simultaneous bilingual acquisition : case study of a French-Russian bilingual child from 2;0 to 4;0Bailleul, Oksana 17 October 2017 (has links)
Cette recherche s’intéresse à l’acquisition du bilinguisme précoce simultané dans un contexte de mixité familiale français-russe. Les recherches récentes dans ce domaine ont montré qu’un ensemble de facteurs tels que l’input parental, ainsi que les stratégies discursives familiales, peuvent expliquer comment l’enfant accède à la parole dans ce contexte (Döpke, 1998 ; Lanza, 1997, 2004 ; De Houwer, 2009 ; King et Fogle, 2013 entre autres). L’enfant bilingue a été enregistrée en interaction spontanée et naturelle avec ses deux parents respectifs sur une durée de deux ans (2;00 à 4;00 ans). Le corpus total est constitué de 68 heures d’enregistrement et l’échantillon analysé a été restreint à 28 heures de transcriptions. Les résultats montrent que la fréquence de l’exposition à l’input et les pratiques langagières familiales ont un impact considérable sur les rapports émergents entre les deux langues à un âge précoce. Il découle de notre analyse que l’enfant développe une forme dominante du bilinguisme et passe progressivement à l’usage harmonieux des deux langues vers 3 ans. Ce passage est accompagné des changements du paysage sonore et de la fréquence de l’exposition à l’input en russe. Un décalage dans l’apparition des catégories grammaticales a été noté : l’acquisition du français suit les modalités générales observées chez les enfants monolingues français, tandis que celle du russe connaît un décalage substantiel. Les transferts interlangues au niveau du lexique, de la morphologie (les fillers) et de la syntaxe permettent de soutenir l’existence des compétences sous-jacentes communes. / This study focuses on language acquisition of a bilingual child growing up in a French-Russian speaking family. Recent research has shown that a range of factors such as parental input frequency, family discourse strategies can explain the language development processes which take place withing a bilingual family (Döpke, 1998 ; Lanza, 1997, 2004 ; De Houwer, 2009 ; King et Fogle, 2013, etc.) The goal is to understand how language exposure, family language policies and input frequency influence the child’s bilingual acquisition in this particular context. For doing that, the child was being recorded during spontaneous and natural interaction with both of her parents for the period of two years (from 2;00 to 4;00). The overall corpora are composed of 68 recording hours, while the analysed sample is based on 28 hours of transcribed data. The data gathered in this study strongly suggest the existence of clear correlation between input frequency, parental discourse strategies and child’s linguistic competence in both languages. The findings from the research show a shift from dominant bilingualism to the harmonious use of both languages at the age of 3. This shift is accompanied by the changes of the child’s linguistic soundscape, the use of parental discourse strategies and input frequency in Russian. The grammatical-categories emergence is characterized by a strong discrepancy in both languages: the acquisition of French follows developmental paths of French monolingual children, while Russian is acquired with a substantial time delay. The crosslinguistic influences, lexical, morphological and syntactic, support the idea of a common underlying proficiency.
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