Experimental technique for evaluating ADC aperture jitter in the frequency domain

The internal timing uncertainty of Analog-to-Digital Converters (ADCs), generally referred to as aperture jitter, is most commonly provided by manufacturers as a single quantitative value representing the total Root-Mean-Square (RMS) jitter. However, for narrow-band applications, only a certain portion of the phase noise corresponding to aperture jitter is relevant to the ADC acquisitions. In this work, a comprehensive experimental approach is proposed for characterizing aperture phase noise in the frequency domain. The utilized measurement setup is based on two nominally identical ADC channels performing acquisitions through a non-IQ sampling scheme, eventually allowing for the separate identification of correlated and uncorrelated phase noise. The impact of the input-stage additive noise is also examined and de-embedded within the proposed measurement procedure. The methodology is applied to characterize a commercial sample-and-hold ADC, separately identifying a white noise component of −147.71 dBc/Hz and a flicker noise component of −113.81 dBc/Hz. The measured jitter value integrated in the full Nyquist bandwidth is well aligned with the RMS aperture jitter reported by the manufacturer.