  The time evolution of a squeezed coherent state conditioned by the results of
a single and double heterodyne measurement is discussed. The mean values of
quadratures as well as the dynamics of quadrature uncertainties have been
obtained within the framework of the theory of continuous measurements based on
filtration equations. It has been found that while the mean values depend on
the measured noise, the uncertainties in the optical quadratures are
deterministic. Explicit solutions for the latter have been provided. Finally, a
time development of the squeeze parameter for the posterior squeezed coherent
state has been found.
