Sökning: "impedance mismatch"

Visar resultat 1 - 5 av 18 avhandlingar innehållade orden impedance mismatch.

  1. 1. Reconfigurable Impedance Matching Networks for Radio Receivers

    Författare :Peter Sjöblom; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Telekommunikationsteknik; Telecommunication engineering; Elektronik; Electronics; reconfigurable matching; switched capacitor; antenna tuning unit; impedance tuning unit; High frequency technology; Elektroteknik; microwaves; Högfrekvensteknik; mikrovågor;

    Sammanfattning : Mobile phones become smaller but include more advanced functions for every new generation. This paradox is possible since reduced transistor size and increased integration of digital building blocks free space for new functions. LÄS MER

  3. 2. Run-Up Transient Analysis for Salient Pole Wound Field Synchronous Motors : Field winding and power electronics implications for a smoother and cooler asynchronous start

    Författare :Roberto Felicetti; Urban Lundin; Andreas Binder; Uppsala universitet; []
    Nyckelord :apparent resistance; cable modeling; current control; transmission line model; eddy currents; field winding; frequency analysis response; Fourier Transform; impedance mismatch; main inductance; overvoltage; parasitic capacitance; partial discharge; quality factor; ringing; slew rate; stray inductance; voltage gradient; winding resonance frequency; asynchronous start; run-up; torque ripple; reluctance torque; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Salient Pole Wound Field Synchronous Machines have better efficiency at full load than asynchronous machines of the same capability. Moreover, where asynchronous machines need inherently to draw a magnetizing current from the grid, Salient Pole Wound Field Synchronous Machines can work efficiently at unity power factor. LÄS MER

  4. 3. Voltage Transients in the Field Winding of Salient Pole Wound Synchronous Machines : Implications from fast switching power electronics

    Författare :Roberto Felicetti; Urban Lundin; Jon Kjellin; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; apparent resistance; cable modeling; current control; transmission line model; eddy currents; field winding; frequency analysis response; Fourier Transform; impedance mismatch; main inductance; overvoltage; parasitic capacitance; partial discharge; quality factor; ringing; slew rate; stray inductance; voltage gradient; winding resonance frequency;

    Sammanfattning : Wound Field Synchronous Generators provide more than 95% of the electricity need worldwide. Their primacy in electricity production is due to ease of voltage regulation, performed by simply adjusting the direct current intensity in their rotor winding. LÄS MER

  5. 4. Pulmonary ventilation and perfusion assessed by electrical impedance tomography - Experimental studies in pigs

    Författare :Anneli Fagerberg; Göteborgs universitet; []
    Nyckelord :electrical impedance tomography; V Q matching; pig; endotoxinaemic ALI; ACE inhibitor;

    Sammanfattning : Pulmonary ventilation and perfusion and ventilation/perfusion (V/Q) matching determine gas exchange in every lung unit in the healthy state and in the pathologically altered lung. Mismatch of V and Q lead to hypoxaemia and hypercapnia and monitoring of V/Q relations are thus important in critical illness. LÄS MER

  7. 5. Active Transmitter Antenna Array Modeling for MIMO Applications

    Författare :Parastoo Taghikhani; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; beam steering; Active antenna array; active impedance; hybrid beamforming transmitter; MIMO transmitter; far-field nonlinear distortion; millimeter wave; modeling.;

    Sammanfattning : The rapid growth of data traffic in mobile communications has attracted interests to the Multiple-Input-Multiple-Output (MIMO) communication systems at millimeter-wave (mmWave) frequencies.  MIMO systems exploit active transmitter antenna arrays for higher energy efficiency and providing beamforming flexibility. LÄS MER