General Analysis of Feedback DAC´s Clock Jitter in Continuous-Time Sigma-Delta Modulators

This brief describes a framework for the analysis of continuous-time sigma-delta (ΣΔ) modulators (CTSDM) in the presence of a feedback digital-to-analog converter (DAC)´s clock jitter using the discrete-time Volterra series. A time-domain mixing operation between jitter and CTSDM´s digital output sequence is modeled with a second-order Volterra operator. The resulting closed-form jitter-induced CTSDM´s output power spectral density is simple and includes the effects of the following: 1) quantization noise power; 2) input signal power and frequency; 3) CTSDM´s quantization noise transfer function; 4) DAC´s pulse shape; and 5) colored jitter. A third-order CTSDM is analyzed as a test bed. Excellent agreement between theoretical predictions and behavioral simulations is observed.