Sharif Digital Repository

In this thesis interferometric method is used in the frequency discriminator based on classic delay line technique for phase noise measurement of microwave oscillators at X-band. In this method no reference oscillator is needed for phase noise measurement. Beacause of carrier suppression, we can use low noise amplifier in linear regimeandthereforethe added noise to the phase detector, is reduced and the sensitivity of the system is improved consequently. Moreover cross correlation method isapplied to improve the sensitivity of classic delay line frequency discriminator technique. It has been shown that up to 15 dB improvement is achievable at far from carrier offsets.
 

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... 

In the present work we first introduced ILIDS and review the theory of interferometry and light scattering from droplets. Bases on ILIDS method, droplets are irradiated by monochrome sheet laser, where the superposition of reflected and first-order refracted beams form a parallel fringe pattern at out of focus plane on the imaging sensor in the forward-scatter region. This pattern can be related to the droplet size by using simple geometrical optics. For the present work, an image processing algorithm is utilized to capture weak and noisy images of droplets to reduce the lost data in the sizing procedure. Since ILIDS method is applied for small and dilute spray, it is suitable for...