Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / Thesis presented in partial fulfilment of the requirements for the degree Master of Science in Engineering at the University of Stellenbosch / ENGLISH ABSTRACT: In 1966, D.B. Leeson presented his model on phase noise in a letter entitled A Simple Model of Feedback Oscillator Noise Spectrum. This model usually requires an additional e ffective noise figure in order to conform with measured results. (This e ffective noise fi gure has to be determined by means of curve-fi tting Leeson's model with the measured results.) The model is, however, relatively simple to use, compared with other more accurate phase noise models that have since been developed and which can only be solved numerically with the aid of computers. It also gives great insight regarding component choices during the design process. Therefore several experiments were conducted in order to determine conditions under which Leeson's model may be considered valid and accurate. These experiments, as well as the conclusions drawn from their results, are discussed in this document. / AFRIKAANSE OPSOMMING: In 1966 stel D.B. Leeson sy faseruis model bekend in 'n brief getiteld A Simple Model of Feedback Oscillator Noise Spectrum. Hierdie model vereis gewoonlik die gebruik van 'n bykomende e ektiewe ruissyfer, sodat die model ooreenstem met die gemete resultate. (Hierdie e ektiewe ruissyfer kan slegs bepaal word deur middel van krommepassings tussen Leeson se model en die gemete resultate.) Die model is egter relatief eenvoudig om te gebruik in teenstelling met ander, meer akkurate, faseruis modelle wat sedertdien ontwikkel is en slegs met behulp van rekenaars opgelos kan word. Dit bied ook onoortre ike insig ten opsigte van komponent keuses tydens die ontwerpsproses. Om hierdie rede is verskeie eksperimente uitgevoer met die doel om toestande te identi seer waaronder Leeson se model as geldig en akkuraat geag kan word. Hierdie eksperimente, asook die gevolgtrekkings wat van hul resultate gemaak is, word in hierdie dokument behandel.