  A novel scheme for determining the pseudo-Stark splitting of optical lines
has been suggested and tested in experiment. The scheme allows one to observe
the beating of a photon echo waveform under conditions of overlap in time
between a weak electric pulse and its echo- pulse. The pseudo-Stark splitting
is equal to the inverse average modulation period of the echo waveform. The
photon echo beating of the R1-line in Ruby has been observed. The dependence of
the inverse average modulation period of the echo waveform on the average value
of the electric field over the optically excited volume has been found. The
obtained values of the pseudo-Stark parameter are in good agreement with known
literature data.
