Noise analysis of modulated self-oscillating mixers

In this work, the envelope transient method is applied for the noise analysis of self-oscillating mixers, with modulated input-signals. Due to the smallness of the noise perturbations, the noisy envelope-transient system can be linearized about the noiseless modulated steady-state solution. This enables a substantial reduction of the computational effort and better insight into the noise behavior of these autonomous systems. The study has been initially carried out in a simplified self-oscillating mixer. Then, it has been applied to a FET-based 5.5 GHz - 0.5 GHz frequency down-converter, with very good agreement with the experimental results.