prototype filter prototype filters electronic filter designs template produce modified filter design particular application example design desired filter scaled transformed seen regard electronic filters especially linear passive filters principle method applied kind linear filter signal processing including mechanical acoustic optical filters filters required operate different frequencies utility prototype filter comes property filters derived applying scaling factor components prototype filter design need carried filters obtained simply applying scaling factor especially useful ability transform case transform simple scale factor meant indicate category filter possesses usual possible particular possible filter multiple fact treatments filter considered type multiple filter having commonly prototype filter expressed filter techniques possible parts article section rely reader knowledge complex representation knowledge frequency domain representation signals low pass prototype prototype low pass filter corner frequency angular frequency occasionally frequency instead likewise nominal characteristic filter set principle non zero frequency point filter response reference prototype design example filters corner frequency usually defined highest frequency maximum case image filters older design method modern network synthesis filters use cut frequency point cut defined point type filter prototype filter produce filters class order instance fifth order filter prototype converted fifth order filter transformed order filter fifth order filter frequency scaling prototype filter scaled frequency required following transformation formula value frequency cut frequency prototype desired value transfer function filter transformed formula readily seen achieve non components filter transformed formula formula scaling scaling invariably scaling fixed resistance filter nominally taken fixed resistance carry scaling nominal element filter transformed formula convenient elements scale instead formula readily seen achieve non components filter scaled formula formula scaling effect transfer function filter providing terminating scaling applied usual combine frequency scaling single step formula formula transformation general filter transformed replacing occurs transfer function function turn leads transformation components filter component frequency scaling trivial case transformation corresponding transformation frequency transformation required case formula point filter corresponding prototype transfer function transforms formula transformed according formula transformed formula quantities component value prototype case required frequency transformation formula factor equal formula lower upper frequency points respectively response corresponding prototype formula formula absolute frequency filter note frequency scaling prototype prior transformation affect frequency instead affects final filter transfer function filter transformed according formula transformed series formula transformed parallel formula required frequency transformation formula transformed parallel formula transformed series formula multi band filters multiple obtained applying general transformation formula number expression corresponds number required filters viewed special cases expression terms zero appropriate filters regarded combination filter multiple filters expressed terms multiple filter way seen transformation represents general case viewed special cases response obtained convenient component transforming multiple instead multiple required transformation cases formula alternative prototype treatment image filters provided alternative basis constructing prototype based frequency domain prototypes correspond particular transformed giving special significance makes method pleasing common use prototype considers filter sections components transformation carried port network terminal transfer function expressed terms product series filter half section article image description half sections quantity adding prototype generally complex quantity formula general functions properly write formula image filters possible obtain filters different classes constant filter prototype means different kind transformation composite image filter constant filters constant reason filters classes given terms constant formula case networks quantity zero need considered ranges centre cut frequency continues increase negatively regardless filter designed obtain required following transforms constant prototype scaled formula independent variable response plot formula prototype formula formula formula
Prototype filter