Study on Residual Phase Noise Effect of Sampling Clock in Fully Digital Phase Noise Measurement

Abstract

In this paper, we examined the phase noise residual effect of sampling clock in fully digital phase noise measurement. When measuring the phase noise of the oscillator, it is necessary to prepare a reference oscillator (REF) in addition to the DUT. Although the frequency of the DUT and REF is the same in the phase noise measurement using the conventional PLL, the frequency of the DUT and the REF is different because the PLL is not used in the fully digital phase noise measurement. In particular, it is clarified that fatal measurement error occurs when the frequency of the measured oscillator and the reference oscillator are different.