Frequency-Domain Analysis of Reconfigured Incremental ΔΣ ADCs on the Example of the Exponential Phase

In this paper, analysis of linear time-variant systems is applied to incremental Delta-Sigma (I-DS) ADCs with periodic architectural reconfiguration in the frequency domain. The analysis will then be applied to the example of linear-exponential I-DS ADCs as a state-of-the-art dynamic reconfiguration technique. It is shown how a matched reconstruction filter of the reconfigured linear-exponential incremental Delta-Sigma modulator (I-DSM) can be mathematically derived. Using the calculated overall transfer functions of the linear-exponential I-DS ADC, accurate performance predictions can be given. The proposed method allows the accurate prediction of performances and gives insight and understanding of the performance improvements and trade-offs achieved by reconfiguration techniques in I-DS ADCs in general and the exponential phase in particular.