Direct-digital phase-noise measurement

Abstract

We have completed a phase 1 SBIR project to develop technology for direct phase-noise measurements. This new approach to phase-noise measurements uses fast analog-to-digital converters to digitize the input RF signal and performs all down-conversion and phase detection functions by digital signal processing. It has several significant advantages over analog phase-noise measurement techniques: there is no external phase-lock loop; oscillators can be compared at all different frequencies; amplitude and phase noise may be measured simultaneously; the spectrum and Allan variance may be computed simultaneously; and complex calibration techniques are eliminated.