  The nonlinear Schrodinger (NLS) equation under the box-type initial
condition, which models general multiple pulses deviating from pure solitons,
is analyzed. Following the approximation by splitting the initial pulse into
many small bins [G. Boffetta and A. R. Osborne, J. Comp. Phys. 102, 25 (1992)],
we can analyze the Zakharov-Shabat eigenvalue problem to construct transfer
matrices connecting the Jost functions in each interval without direct
numerical computation. We can obtain analytical expressions for the scattering
data that describe interfering radiation emitted from initial pulses. The
number of solitons that appear in the final stage is predicted theoretically,
and the condition generating an unusual wave such as a double-pole soliton is
derived. Numerical analyses under box-type initial conditions are also
performed to show that the interplay between the tails from decaying pulses can
affect the asymptotic profile.
