Ferroelectric Tunnel Junctions (FTJs) op- erating as memristors are promising electron devices to realize artificial synapses for neuromorphic computing. But the understanding of their operation requires an in-depth electrical characterization. In this work, an in- house validated experimental setup is employed along with novel experimental methodologies to investigate the large-signal (LS) and small-signal (AC) responses of FTJs. For the first time to our knowledge, our exper- iments and physics-based simulations, help to explain the discrepancies between LS and AC experiments reported in previous literature.