  We study the variation of the differential conductance $G=dj/dV$ of a normal
metal wire in a Superconductor/Normal metal heterostructure with a cross
geometry under external microwave radiation applied to the superconducting
parts. Our theoretical treatment is based on the quasiclassical Green's
functions technique in the diffusive limit. Two limiting cases are considered:
first, the limit of a weak proximity effect and low microwave frequency,
second, the limit of a short dimension (short normal wire) and small
irradiation amplitude.
