Loading...

Phase Noise Reduction of Microwave Oscillator Using Interferometric Technique

Salarpour, Mehdi | 2009

640 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39729 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Banayi, Ali
  7. Abstract:
  8. In today’s microwave communication, oscillators play a very important role as signal sources, so, the design of an oscillator with suitable parameters can affect the final performance of a communication system. Among different parameters, phase noise is of utmost importance since this parameter can lead to interference in multi-frequency channel systems and thus its estimation and measurement is vital. In an oscillator, in addition to measurement, the most important problem is to reduce phase noise. In fact, for improving the performance of a transmitter-receiver ( e.g. receiver sensitivity ), one of the solutions is using a local oscillator with low phase noise. Our purpose in this project is to design and fabricate an oscillator in X-band near 10GHz frequency whose phase noise is improved in comparison with a free running one. To do so, some methods are suggested among which frequency discriminator with microwave interferometric method is the most effective one. This discriminator extracts phase noise of the free running oscillator using a resonator with high quality factor, a low noise microwave amplifier and carrier suppression technique and then reinjects it to oscillation loop by a voltage controlled phase shifter. With regard to applying carrier suppression method, the discriminator has a low noise floor ( high sensitivity ) and therefore, the final oscillator phase noise is reduced after compensation due to this low noise floor. It should be said that in the implementation stage, critical elements such as resonator, low noise microwave amplifier and voltage controlled phase shifter are designed separately. For other elements, we use prepared ones like passive waveguide components( coupler, attenuator, phase shifter, hybrid 180, circulator and isolator ) and coaxial amplifier modules.

  9. Keywords:
  10. Phase Noise ; Microwave Oscillator ; Resonator ; Frequency Discriminator ; Interferometric Method ; Carrier Supperssion

 Digital Object List

  • محتواي پايان نامه
  •   view

 Bookmark

No TOC