Reduction of phase noise in single transistor oscillators

In this paper good phase noise has been taken as the predominant requirement for any oscillator. Many apparently different single transistor oscillator types can be analysed using the same fundamental phase noise model. This model indicates the noise match and power match conditions required to give the best phase noise. Noise matching gives only a small advantage. Phase noise can be optimised almost automatically by minimising tuned circuit losses and maximising tuned circuit voltages. It is shown that the Clapp oscillator is a good design for low phase noise, but there is a modified Clapp design which could give better phase noise performance at high frequencies