Dual carrier suppression interferometer for measurement of phase noise

A new scheme for phase noise measurement is presented, based on dual stage suppression of the carrier and synchronous detection of the noise sidebands of the device being tested. This scheme features real time output and intr insically low instrument flicker. A prototype shows a residual flicker as l ow as -160dBrad(2)/Hz at 1Hz off the 100MHz carrier. Other implementations are possible, from 1MHz to several gigahertz. Applications include the nois e characterisation of components and the design of innovative ultrastable o scillators.