The Radiospurs Filter Tool Site

This is a dedicated site for design tools related to the Radiospurs browser site. The tools are free to browse and use, but registration is required for extended usage. Supporter clients receive un-restricted usage.

A new Spice analysis has been incorporated to calculate the power/voltage/currents in a power filters. Go to the Design tab, the More... tab

Passive Filters

These are a class of filters using only the three basic elements RLC (Resistor, Inductor, Capacitor). There are standard filter types Butterworth, Chebychev, Bessel, Guassian, Legendre, Linear Phase, Transitional, Elliptical are just some. The common formats are LP (Low pass), HP (High Pass), BP (Band Pass), BS (Band Stop or notch), AP (All Pass). Often used as prototypes for other filter transformations. Note: Altough all calculations are done with 64bit arithmetic, the presentation is with E192 components and (more importantly) the graphical results are for these E192 values. ie: practical NOT theoretical.

More to the point and practical would be to re-calculate the design with E96 (1%) resistors, E48 (2%) capacitors and E24 (5%) inductors for lumped elements. however if this is a Band 11 high power filter there should be no problem with 2% inductors and 0.5% capacitors.

Passive Filters

Microwave Filters

All the previous filters are discrete, in that the individual components occupy little volume in comparision with the wavelength of the signal being processed. As a rule of thumb if the size of the component goes beyond 0.1 wavelength there is a transition to using distributed techniques. Try out your interdigital, parallel coupled, capacitive gap filters.

Microwave Filters