Singly and Doubly Terminated Filters

Doubly terminated filters are filters with a finite non zero termination at both ends. Single terminated filters are filters with a finite nonzero termination at one end, and an open or shorted termination at the other. Equally terminated filters are doubly terminated filters with identical finite nonzero terminations at each end.

Equally terminated filters usually, but no always optimized for the best reflection response. with a finite nonzero source resistance. In some cases, it is not physically possible to synthesize with equal terminations, and in others a step up/down transformer is required.

FilterSolutions supports singly, doubly, and equally terminated filters. Singly terminated filters are supported for shorted voltage sources, open current sources, and open loads.

Doubly and Equally Terminated Filters:

Enter the load and source resistance into the appropriate text entries on the Passive control panel. Check the reflections response to insure you are getting the desired reflections.

Singly Terminated Filters:

To synthesize a shorted voltage source filter, enter "0" in the Source Res text entry box and select Voltage source.

To synthesize an open current source filter, enter "Inf" in the Source Res text entry box and select Current source.

To synthesize an open load filter, enter "Inf" in the Load Res text entry box and select Current source.

Impedance Matching

Purely reactive loads and sources may sometimes be incorporated directly into a singly terminated filter. For example, if a filter load is exactly one 1mH and an open end filter design requires 2mH, the 2mH inductor may be composed of a 1mH inductor in series with the load. Likewise, if the filter design requires 500uH, the 500uH inductor may be composed of a 1mH indictor in parallel with the load.