Filternaut provides an easy interface to explore the behaviour and response of various filters. The resulting filters are normalized for a pass band frequency of 1 radian/second as is standard when designing analog filters. Various transforms are then applied that convert the reference design to:
Evenually I plan to add the above mentioned transforms to Filternaut but for now it's limited to reference filter design.
One additional note, I don't have a filter order estimation function for either the Bessel or Optimum L filters, so both of these filter types are specified explicitly by order rather than pass band and stop band characteristics.
Enjoy exploring!