  Ferroelectric tunnel junctions (FTJs) are a class of memristor which promise
low-power, scalable, field-driven analog operation. In order to harness their
full potential, operation with identical pulses is targeted. In this paper,
several weight update schemes for FTJs are investigated, using either
non-identical or identical pulses, and with time delays between the pulses
ranging from 1 us to 10 s. Experimentally, a method for achieving non-linear
weight update with identical pulses at long programming delays is demonstrated
by limiting the switching current via a series resistor. Simulations show that
this concept can be expanded to achieve weight update in a 1T1C cell by
limiting the switching current through a transistor operating in sub-threshold
or saturation mode. This leads to a maximum linearity in the weight update of
86% for a dynamic range (maximum switched polarization) of 30 {\mu}C/cm2. It is
further demonstrated via simulation that engineering the device to achieve a
narrower switching peak increases the linearity in scaled devices to >93 % for
the same range.
