AM noise impact on low level phase noise measurements

摘要

The influence of the source AM noise in microwave residual phasennoise experiments is investigated. The noise floor degradation problem,ncaused by the parasitic detection of this type of noise by annimperfectly balanced mixer, is solved thanks to a refinement of thenquadrature condition. The parasitic noise contribution attributable tonthe AM to PM (phase modulation) conversion occurring in the device underntest is minimized through the development of a dedicated microwavensource featuring an AM noise level as low as -170 dBc/Hz at 10 kHznoffset from a 3.5 GHz carrier