A digital filter that improves the signal-to-noise ratio of the response of a FSCW (Frequency Stepped Continuous Wave) scheme is presented. An improvement in signal-to-noise ratio represents an enhanced readout distance. This work considers this architecture as an interrogation unit for SAW tags with time and phase encoding. https://www.spidertattooz.com/China-Glaze-Beaches-Toes-0-5-oz-84652-p12283/