Filter-chain-creating, digital signal-processing structure, for performing frequency band analysis and selection, which structure features a time-slice-based digital fabricating/instantiating engine, and engine-software-operating structure designed to operate the engine in a time-slice-based fabrication mode to create a chained arrangement of at least one of (a) Type-I, and (b) combined Type-I and Type-I wave digital filter (WDF) agencies in an overall, composite WDF structure to function for frequency band analysis and selection.