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Distribution of albacore (Thunnus alalunga) in the Indian Ocean and its relation to environmental factors
No full textSpatial and Temporal Distribution Patterns of Bigeye Tuna (Thunnus obesus) in the Indian Ocean
No full textA 1GS/s 6-bit 48mW A/D Converter
No full text本研究是採用兩階段式 (Two-step) 的架構，來實現高速的類比數位轉換器(Analog-to-Digital Converter)。在此論文中提出一個快速穩定的方法 (fast-settling method)來縮短運算放大器的上升時間以及經由重新安排時脈圖來使得電路可以工作的更加有效率。本晶片使用台積電0.13-μm CMOS製程製作，解析度為六位元，操作時脈頻率為1 GS/s，INL為+0.3/-0.3 LSB，DNL為+0.49/-0.49 LSB，在輸入信號頻率為奈奎斯特頻率的情況下，SFDR為49.2dB，SNDR為31.3dB，在1.2伏特的供應電壓下，消耗功率為 50mW。A 1 GS/s 6-bit CMOS two-step ADC using fast-settling method and through timing rearrangement is demonstrated in a standard 0.13-μm CMOS process. The proposed method shortens the slew time of OPAMP in MDAC and the timing arrangement makes the circuits operated more efficient. The prototype circuit exhibits an INL of +0.3/-0.3 LSB and a DNL of +0.49/-0.49 LSB. The SNDR and SFDR achieve 31.3 and 49.2 dB at 1 GS/s for Nyquist input frequency. The ADC consumes 50 mW at 1.2V supply and occupies an active chip area of 0.16 mm2.ACKNOWLEDGMENT I
ABSTRACT III
TABLE OF CONTENTS Ⅴ
LIST OF FIGURES Ⅶ
LIST OF TABLES Ⅸ
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 FUNDAMENTALS OF ANALOG-TO-DIGITAL CONVERTER 2
2.1 PERFORMANCE METRICS 2
2.1.1 Signal-to-Noise Ratio (SNR) 2
2.1.2 Total Harmonic Distortion (THD) 2
2.1.3 Spurious-Free Dynamic Range (SFDR) 3
2.1.4 Signal-to-Noise and Distortion Ratio (SNDR) 3
2.1.5 Effective Number of Bits (ENOB) 3
2.1.6 Differential Nonlinearity (DNL) 4
2.1.7 Integral Nonlinearity (INL) 5
2.2 HIGH-SPEED AND LOW RESOLUTION ADC ARCHITECTURES 6
2.2.1 Two-step ADC 7
2.2.2 Full flash ADC 8
2.2.3 Folding and Interpolating ADC 9
CHAPTER 3 TIME-INTERLEAVED A/D CONVERTER 12
3.1 INTRODUCTION 12
3.2 TIME-INTERLEAVED A/D CONVERTER 12
3.3 CHANNEL MISMATCH EFFECTS 14
3.3.1 Offset mismatch effect 14
3.3.2 Gain mismatch effects 16
3.3.3 Clock timing error effects 17
3.3.4 Combined channel mismatch effects 18
CHAPTER 4 PROPOSED TIMING DIAGRAM AND FAST-SETTLING METHOD 21
4.1 CONVENTIONAL TWO-STEP ADC TIMING DIAGRAM 21
4.2 PROPOSED TIMING DIAGRAM 23
4.3 FAST-SETTLING METHOD 25
CHAPTER 5 CIRCUIT IMPLEMENTATION 29
5.1 ARCHITECTURE 29
5.2 MDAC 30
5.2.1 Residue of MDAC 32
5.3 OPERATIONAL AMPLIFIER 34
5.4 COMPARATOR 35
5.5 DIGITAL CIRCUIT FOR FAST-SETTLING 37
5.6 BIAS CIRCUIT AND CMFB CIRCUIT 38
5.7 CLOCK GENERATOR 39
5.8 SIMULATION RESULT 41
5.8.1 Operational amplifier simulation 41
5.8.1.1 AC analysis 41
5.8.1.2 Transient analysis 42
5.8.2 FFT test 43
5.8.3 Summary 44
CHAPTER 6 PERFORMANCE 45
6.1 FLOOR PLAN AND LAYOUT CONSIDERATIONS 45
6.2 TEST SETUP 48
6.3 PCB DESIGN 50
6.4 EXPERIMENT RESULT 54
6.4.1 Static performance 55
6.4.2 Dynamic performance 56
6.5 SUMMARY 59
CHAPTER 7 CONSLUSIONS 61
BIBLIOGRAPHY 6
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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