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Visar resultat 1 - 5 av 7 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Design and Characterization of MMIC IF VGA and Small Signal CMOS Millimeter Wave Amplifiers

    Författare :M. Anowar Masud; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; BCB; CMOS; GaAs; LNA; VGA; MMIC; HEMT;

    Sammanfattning : The main aim of this work is to demonstrate the easibility of designing and characterizing monolithic microwave integrated circuit (MMIC) variable gain amplifiers (VGA) and small signal amplifiers in III-V (GaAs) and 90 nm CMOS technologies, respectively. The VGA is studied at the IFfrequency of 2. LÄS MER

  3. 2. Integrated Variable-Gain and CMOS Millimeter-Wave Amplifiers

    Författare :Mohammad Anowar Masud; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LNA; MMIC; FinFET; CMOS; HEMT; GaAs; WLP; VGA; BCB;

    Sammanfattning : Variable Gain Amplifier finds extensive use in the high frequency demonstrators specially those operating in the millimeter-wave regions and beyond where the incoming RF signal level can have wide variations. To maintain a constant signal level an IF VGA has been designed that can offer a dynamic variation of gain as much as 45 dB together with a high maximum gain and a low noise figure. LÄS MER

  4. 3. Quantifying the quality of medical x-ray images. An evaluation based on normal anatomy for lumbar spine and chest radiography

    Författare :Anders Tingberg; Malmö Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Clinical physics; normal anatomy; free response forced error FFE ; receiver operating characteristics ROC ; visual grading analysis VGA ; European image criteria; quantifying clinical image quality; radiology; tomography; medical instrumentation; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering;

    Sammanfattning : Optimisation in diagnostic radiology requires accurate methods for determination of patient absorbed dose and clinical image quality. Simple methods for evaluation of clinical image quality are at present scarce and this project aims at developing such methods. LÄS MER

  5. 4. Methods Used in Quality Assurance and Optimization in Nuclear Medicine Imaging and Imaging Systems

    Författare :Sven-Åke Starck; Sten Carlsson; Göteborgs universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; phantom; image quality; attenuation coefficients; detective quantum efficiency DQE ; digital filtering; iterative reconstruction; bone scintigraphy; bone SPECT; visual grading analysis VGA ; ROC-analysis;

    Sammanfattning : .... LÄS MER

  7. 5. CALLUM Linear Transmitter - Architecture and Circuit Analysis

    Författare :Roland Strandberg; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Telekommunikationsteknik; Telecommunication engineering; loop time delay; modulation negative feedback; spectral emissions; baseband model; CALLUM; Linear transmitter architecture; power amplifier linearization;

    Sammanfattning : This doctoral dissertation presents a study of linear radio transmitters based on the combined analog locked loop universal modulator (CALLUM) approach. Linear architectures such as CALLUM are very attractive for power-efficient operations, since they have no fundamental limitations prohibiting a 100% efficiency for all envelope levels, without sacrificing the potential of a linear transmission. LÄS MER