Uncertainty characterization of a two channels digital analyzer as a wideband phase comparator

This paper reports some tests and results concerning the phase characterization of a two channel digital analyzer, used as wideband phase comparator. The algorithm for the determination of the phase difference is analyzed in order to derive its uncertainty contribution to the phase evaluation process. Some tests with simulated signals of known phase differences and experiments using either the same signal or opposed ones in the two channels of the digitizer built have been performed. The results show that the uncertainty contribution, of the phase difference, due to the rms noise of the digitizer at sampling frequency of 10 MHz is about 7×10^-8 at 20 kHz.