Time-varying circuit approaches for software defined and cognitive radio applications

A brief overview of the recently developed "Filtering by Aliasing" (FA) technique is presented. FA utilizes a linear, periodically time varying (LPTV) circuit followed by a sampler to achieve sharp apparent filters from a continuous-time (CT) input to a discrete-time (DT) output. Applications to RF frontends and spectrum scanners along with the effect of circuit parasitics on achievable performance is also described.