This study was a phase-noise measurement of an electronic oscillator employing optoelectronic measuring approaches. In the first part, a formulation of tne spectral quantities of the noise are presented. A derivation of Leeson's equation for phase noise follows, where the oscillator is treated as a linear time-invariant system. The next section is dedicated to an overview of the methods for phase-noise measurements. The direct method, the phase-detector method and dual-channel cross-correlation method are briefly described. A separate section is dedicated to the frequency-discriminator method in which the transfer function of a generic frequency discriminator is presented. Different implementations of the delay element are treated. A frequency discriminator with an optical delay line is gradually developed.
In the second part, fabricated components of the measuring system are presented. These include an optical receiver, amplifiers, filters and mixers. A presentation of the measuring system follows,with a description of the calibration and the measurement of phase noise. The measurement is performed on three different signal sources at a frequency 10.5 GHz. The obtained results are reproducible for different variations of the measurement setup and they agree with the results obtained using the direct method. Finally, a few potential improvements to the setup are presented.
|
