  We present the reconstruction of the Wigner function of some classical pulsed
optical states obtained by direct measurement of the detected-photon
probability distributions of the state displaced by a coherent field. We use a
photodetector endowed with internal gain, which is operated in the non-
photon-resolving regime. The measurements are performed up to mesoscopic
intensities (up to more than 30 photons per pulse). The method can be applied
to characterize nonclassical continuous-variable states.
