We show how to design one-dimensional systems that in the transmission through a finite potential barrier, in a predetermined way, discriminate between monochromatic waves depending on their wave number. These systems, described by the on-site tight-binding equation, act as filters of different types, with adjustable pass and stop bands. The use of these filters for discrimination of linear wave packets depending on their different velocities is illustrated, and we also comment on the influence of an added nonlinearity.