EXCESS NOISE IN HETERODYNE RECEIVERS

The influence of excess noise above the classical shot noise level in heterodyne receivers is investigated. It is shown how excess noise from the local oscillator (LO), beside thermal and phase noise, influences the system performance. Under carefully controlled experimental conditions, the LO power can be decoupled from excess noise. This yields an optimum LO power to get maximum receiver sensitivity. The optimum LO power is determined by the transition from shot noise dominance to excess noise dominance.