Performance Limits of Generalized Sampling Based 2-Channel Analog-to-Digital Converter

This brief proposes an analog-to-digital converter (ADC) based on Generalized Sampling Theorem and derives a closed form expression of its performance, viz., signal-to-quantization noise ratio (SQNR) and alias-suppression (AS). The ADCs in the 2-channels sample the signal and its filtered version, respectively, at half the Nyquist rate. The outputs of the two ADCs are upsampled by a factor of 2, passed through appropriate reconstruction filters, and then added to give an effective sample-rate which is double that of the sample-rate of each channel ADC. Performance of the proposed ADC has been summarized for simple filters like differentiator, integrator, passive RC low-pass filter, and passive CR high-pass filters. The proposed ADC could therefore be used as an alternative to other popular ADC structures like time-interleaved, frequency-interleaved, and filter-bank ADCs, to achieve high sample-rate with minimal analog circuit overhead.