  A novel kind of shape changing (intensity redistribution) collision with
potential application to signal amplification is identified in the integrable
$N$-coupled nonlinear Schr{\"o}dinger (CNLS) equations with mixed signs of
focusing and defocusing type nonlinearity coefficients. The corresponding
soliton solutions for N=2 case are obtained by using Hirota's bilinearization
method. The distinguishing feature of the mixed sign CNLS equations is that the
soliton solutions can both be singular and regular. Although the general
soliton solution admits singularities we present parametric conditions for
which non-singular soliton propagation can occur. The multisoliton solutions
and a generalization of the results to multicomponent case with arbitrary $N$
are also presented. An appealing feature of soliton collision in the present
case is that all the components of a soliton can simultaneously enhance their
amplitudes, which can lead to new kind of amplification process without induced
noise.
