Ladder Waveguide Filters

A cascade chain of DWF sections, terminated by a pure reflection on the right, is shown in Fig.H.1. Each box enclosing the symbol $k_i(t)$ denotes a scattering junction characterized by that reflection coefficient. While we have mentioned only the Kelly-Lochbaum and one-multiply junction, any type of lossless scattering junction will do [298]. The DWF employs delays between each scattering junction along both the top and bottom signal paths, unlike conventional ladder and lattice filters. As a result, it has a direct physical interpretation as a sampled acoustic tube.

Figure H.1: Waveguide digital filter structure.