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Analysis of Effect of Parametric Oscillation in Phase Noise Degradation in Frequency Multipliers

Ahmadi, Arash | 2009

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 39838 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Banai, Ali
  7. Abstract:
  8. Variation of the input driving power can cause in some varactor and BJT frequency multipliers parametric instability. If parametric oscillations are present in the circuit, output phase noise of the multiplier degrades remarkably in some specific driving levels. Phase noise of the varactor and BJT multiplier is calculated by the conversion matrix method using generalized nodal analysis. By the conversion method the phase noise degradation can be predicted precisely. In the calculation of phase noise the effect of the noise sources that are modulated by the large signal drive and the conversion of components of the internal noise sources of the device to the output spectrum due to circuit nonlinearities are encountered. The added phase noise of a varactor and a BJT frequency doubler in presence of subharmonic oscillation is calculated and the simulation results are compared with the measurements. Both simulations and measurements show phase noise degradation in the output spectrum in presence of subharmonic oscillation. Excessive phase noise degradation is observed for a specific input power level and at the onset of parametric instability. Increasing the input drive level further, the phase noise degradation improves and approaches the expected 20logN, where N is the multiplication factor. By some experiments and phase noise simulations, the flicker noise of the device is found to be the main cause of the phase noise degradation in presence of subharmonic oscillations
  9. Keywords:
  10. Phase Noise ; Parametric Instability ; Large Signal Analysis ; Small Signal Analysis ; Conversion Matrix ; Varactor Frequency Multiplier ; BJI Frequency Multiplier

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