SIMPLE, EXACT MODELS OF SAMPLE-INTERLEAVING DEMODULATORS/MODULATORS FOR QUADRATURE BANDPASS SAMPLING/RECONSTRUCTION

摘要

Bandpass-sampling systems for complex demodulation are now commonplace in the literature, and a few corresponding bandpass-reconstruction systems for modulation have appeared. But their many apparently distinct topologies, filters, and system parameters and the many approaches used in those designs have obscured their common conceptual underpinnings. We present here a simple, unifying approach to the design of such systems, an approach that generalizes the usual two or four parallel processing arms to an arbitrary number of arms and generalizes the usual real digital filters to complex digital filters. Because a straightforward model built around a single, key filter exactly describes any system of this type, custom design of such a system, including optional spectral shaping, reduces to custom digital-filter design.