Influence of constructive sampling theory on the front ends and back ends of SDRs and CRs

Performance of software-defined and cognitive radios (SDRs and CRs) is limited by their analog and mixed-signal front-ends and back-ends mostly because conventional sampling and reconstruction (S&R) circuits are inconsistent with the sampling theory. This neglect of the theory hinders the implementation of novel S&R circuits (NSCs and NRCs) based on the direct interpretation of the sampling theorem. The NSCs and NRCs improve the dynamic range, attainable bandwidth, energy efficiency, reconfigurability, adaptivity, and scale of integration of SDRs and CRs. Principles, benefits, development challenges, and ways of the NSCs and NRCs implementation are discussed.