In experimental investigations of the wake flow behind a plate, a monochromatic (in time) signal is usually observed immediately behind the end of the plate. Downstream, the signal is distorted and then becomes random, i.e., a turbulent flow regime is realized. Theoretically, a branch point is found at the experimentally observed frequency in the spectrum of three-dimensional perturbations of the problem linearized with respect to the steady solution [1]. Mattingly and Criminale [1] attribute all the characteristics of the observed signal to this point. As in other similar investigations, the mechanism of the appearance of the monochromatic signal in the near wake was not elucidated in [1]. In the present paper, the problem of the characteristic oscillations of the flow in the near wake is studied. The appearance of the monochromatic signal is explained by the presence in the near wake of a standing wave of the required frequency, the wave being formed by two scattering points. The first is the end of the plate, and the second the branch point in the spectrum of linear three-dimensional perturbations.