Exact spectra analysis of sampled signals with jitter-induced nonuniformly holding effects

The timing-mismatch/jitter effects in time-interleaved (TI) systems have been traditionally characterized by digital spectra analysis of nonuniformly sampled signals; however, the nature of that output with sample-and-hold (SH) effects has not yet been well established. This paper will present a complete analysis of signal spectra for general TI systems with practical nonuniformly holding outputs imposed by timing-jitter effects. The analysis reveals first the extra spectra representation for different forms of nonuniformly holding signals and then their closed-form expressions of signal-to-noise-and-distortion-ratio (SINAD), in terms of the number of channels, signal frequency, and jitter errors. Such analysis describes both the timing mismatches imposed by random clock-jitter and fixed periodic clock-skew. MATLAB simulation results confirm the accuracy of the derived formula. Finally, such timing effects and the effectiveness of the formula will be demonstrated through the comparison of calculated and simulated results, as well as in some examples of measured data also, obtained from several practical integrated circuit (IC) applications, including a very high-speed data converter, analog front-end (AFE) filtering and an IF sampled-data radio filter.