A method for designing a cascade of digital filters for use in the control of an electrolytic reduction cell by specifying the frequency and time response characteristics of the transfer function of the cascade of digital filters. A sensing verify operation includes one or more sensing cycles relative to one or more demarcation threshold voltages to determine a memory state. A signal processing circuit performs signal processing on camera signals of the plurality of screens to produce a compressed YUV signal. At another shallow water portion of the fiber optic system, nearby where a destination is located, the signal provided on the optical path over the deep water portion is split into a service path and a protection path, to provide redundancy to deal with any fiber cuts that may occur. A stop block limits movement of the movable part in order to align at least one of the switching waveguides with the applicable input waveguide and output waveguide. The query includes customized query predicates against the start time column values and end time column values of a database table.