FilDes is a synthesis program for electronic filter design using lumped element structures. As such, it will find its greatest application between 1 and 1000 MHz. Below this range, active filters are the usual choice; above it, the filters are usually though not always) built using distributed components FilDes should be easy to use for the experienced filter designer as well as the newcomer. Its input requirements are the things that must be known to design a filter with pencil and paper. It outputs lists of components with notation common to the CAD programs SuperCOMPACT STAR SuperSTAR, and others. The component is listed with its value and the term PAR, if it is connected to ground, or SER if it is connected to the next component listed. Another way of stating PAR is SHUNT; par was chosen for consistency with SuperCOMPACT. Bandpass (BP Bandreject (BR Narrow Bandpass (NBP) and Elliptic filters will have LC combinations with the designation PLC if they are connected in a parallel LC configuration or SLC if they are in series configuration, as well as the PAR or SER circuit connection. The filters can be printed to a text mode printer non-postscript) or to a Touchstone(r) format disk file FilDes will run on all PC or compatible machines. Output dis plays are in textmode windows. Memory requirements are well below the common 640 K in today's machines. A CGA or better color monitor is re quired. A math co-processor is not required, but will speed up certain sections dramatically on PC, XT or slower AT type machines Fildes runs under the File Manager from inside Microsoft Windows version 3.1, or from a DOS prompt. I have only run it from the DOS command line in OS/2
