A formulation based on multirate theory is inroduced for analog-to-digital converters using parallel sigma-delta modulators in conjunction with modulation sequences. It is shown how the formulation can be used to analyze a system's sensitivity to channel mismatch errors by means of circulant and pseudo-circulant matrices. It is demonstrated how the time-interleaved-modulated (TIM), Hadamard-modulated (HM) and frequency-band decomposition (FBD) converters can be viewed as special cases of this more general description, and it is shown why the TIM and HM ADCs are sensitive to channel mismatch errors, whereas the FBD ADCs are not.
['Anton Blad', 'Håkan Johansson', 'Per Löwenborg']
A General Formulation of Analog-to-Digital Converters Using Parallel Sigma-Delta Modulators and Modulation Sequences