  We report the progress in the realization of an electronic / optical
simulator for space based, long arm interferometry and its application to the
eLISA mission. The goal of this work is to generate realistic optics and
electronics signals, especially simulating realistic propagation delays. The
first measurements and characterization of this experiment are also presented.
With the present configuration a modest $10^6$ noise reduction factor has been
achieved using the Time Delay Interferometry algorithm. However, the principle
of the experiment has been validated and further work is ongoing to identify
the noise sources and optimize the apparatus.

Instrumentation and Methods for Astrophysics