Analysis of clock jitter in continuous-time quadrature bandpass sigma-delta modulators with NRZ pulses

Abstract

In this paper, the jitter-induced noise is estimated in continuous-time quadrature bandpass sigma-delta modulator. The closedform formulas for the output spectrum of noise caused by clock jitter are derived. The correctness of the obtained analytical results is proved, based on model simulation. The noise introduced by clock jitter increases the in-band noise power, and therefore decreases the signal-to-noises ratio (SNR). The jitter-induced noise power depends on the noise shaping transfer function and the input signal level. The former's optimization gives improvement in the SNR. The dependence on the latter introduces the non-linearity of the modulator.