1,720,964 research outputs found
Design of a Radiofrequency Power Amplifier test setup using a Hybrid-Based RF Amplifier
No full textThe principle focus of this work is how to design, using components generally available on the market, a novel linear RF power amplifier that includes the ability to measure the return loss of the device connected to its output. This extended functionality is achieved by combining two linear RF power amplifiers using 90-degree hybrids. By repurposing the Isolated port (hereinafter referred to as the “error port”, the return loss measurement capability is achieved. This thesis shows how to design such a power amplifier. A DC load line is used to find the starting values for a load-pull analysis. The detailed load-pull analysis is then performed to determine the optimum load and source impedance for the amplifier based on its desired output power and the intended DC supply voltage. In addition, the work shows how to design the input and output matching networks of the linear power amplifier, as well as the DC-feed networks that supply DC power and set the bias point. The output power capability and the ability of the hybrid-coupled linear power amplifier to measure the return loss of the attached load are also discussed in detail. The RF power amplifier was built using PCB technology, the design was verified, and the amplifier performance was measured and compared to expectations derived from modelling.Huvudfokus för detta arbete är hur man designar, med hjälp av i allmänhettillgänglig komponenter på marknaden en linjär effektförstärkare som har en utökad funktion i att mäta reflektionseffekten för enheten som är ansluten till effektförstärkarens utgång.Mätförmågan uppnås genom att kombinera två linjära effektförstärkare med 90-gradershybrider. Genom att återanvända den isolerade porten (hädanefter kallad "fel port" uppnås möjligheten att mäta returförlust. Detta arbete visar hur man designar en linjär effektförstärkare med hjälp av enDC-lastlinje för att hitta startvärdena för load-pull-analysen.Syftet med load-pull-analysen är att hitta den optimala belastningen och källimpedansen för den linjära effektförstärkaren.Baserat på önskad uteffekt samt önskad DC-matningsspänning. Dessutom visar arbetet hur man designar ingångs- och utgångsmatchande nätverk för den linjära effektförstärkarensamt DC-matningsnätverk som levererar DC-ström och ställer in biaspunkten. Uteffektkapaciteten och reflektionseffekten mätningsförmågan hos den hybridkopplade linjära effektförstärkaren presenteras också. RF-effektförstärkaren byggdes med PCB-teknik, designen har verifieratsoch förstärkarens prestanda har mätts och jämförts med förväntningarna från modellering
Design of a Radiofrequency Power Amplifier test setup using a Hybrid-Based RF Amplifier
No full textThe principle focus of this work is how to design, using components generally available on the market, a novel linear RF power amplifier that includes the ability to measure the return loss of the device connected to its output. This extended functionality is achieved by combining two linear RF power amplifiers using 90-degree hybrids. By repurposing the Isolated port (hereinafter referred to as the “error port”, the return loss measurement capability is achieved. This thesis shows how to design such a power amplifier. A DC load line is used to find the starting values for a load-pull analysis. The detailed load-pull analysis is then performed to determine the optimum load and source impedance for the amplifier based on its desired output power and the intended DC supply voltage. In addition, the work shows how to design the input and output matching networks of the linear power amplifier, as well as the DC-feed networks that supply DC power and set the bias point. The output power capability and the ability of the hybrid-coupled linear power amplifier to measure the return loss of the attached load are also discussed in detail. The RF power amplifier was built using PCB technology, the design was verified, and the amplifier performance was measured and compared to expectations derived from modelling.Huvudfokus för detta arbete är hur man designar, med hjälp av i allmänhettillgänglig komponenter på marknaden en linjär effektförstärkare som har en utökad funktion i att mäta reflektionseffekten för enheten som är ansluten till effektförstärkarens utgång.Mätförmågan uppnås genom att kombinera två linjära effektförstärkare med 90-gradershybrider. Genom att återanvända den isolerade porten (hädanefter kallad "fel port" uppnås möjligheten att mäta returförlust. Detta arbete visar hur man designar en linjär effektförstärkare med hjälp av enDC-lastlinje för att hitta startvärdena för load-pull-analysen.Syftet med load-pull-analysen är att hitta den optimala belastningen och källimpedansen för den linjära effektförstärkaren.Baserat på önskad uteffekt samt önskad DC-matningsspänning. Dessutom visar arbetet hur man designar ingångs- och utgångsmatchande nätverk för den linjära effektförstärkarensamt DC-matningsnätverk som levererar DC-ström och ställer in biaspunkten. Uteffektkapaciteten och reflektionseffekten mätningsförmågan hos den hybridkopplade linjära effektförstärkaren presenteras också. RF-effektförstärkaren byggdes med PCB-teknik, designen har verifieratsoch förstärkarens prestanda har mätts och jämförts med förväntningarna från modellering
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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