We analyze for the first time in phase space the soliton type solutions of
fields propagating in a X-(2) medium Analytical expression. are given for t
he Wigner transform and its first and second order moments, for both bright
and dark solitons. The phase space analysis of real field distributions,cl
ose to ideal solitons, is Sound in quantitative agreement with life analysi
s in only the field distribution variable, although it offers more informat
ion.