In this paper we present several novel approaches for designing moving intensity masks in order to exceed the classical resolution limits of incoherent optical systems. The paper deals with two types of masks both based on pulse amplitude modulation (PAM) techniques. The first approach includes one mask that is attached to the input plane. The super resolution in the output plane is obtained by applying a special data readout process of the sensing device. The second approach includes two moving masks: one is attached to the input plane whereas the other to the output plane. In this case both masks are cyclo-stationary. They are based on PAM but only their second order statistics is of interest. Thus a reduced sensitivity to fabrication errors is obtained and no special data readout process is required. In both cases the presented systems enable one to restore high frequencies as well as to process the entire data.