James L. Tonne
110
Freeware
For designing diplexers of both the highpass/lowpass and bandpass/bandstop types.
1
Tonne Software
139
Freeware
Helical is a graphics-intensive bandpass filter design.
Polyphase Microwave
30
Freeware
Quadrature modulators generate any bandpass RF modulation including QPSK.
1
Schematica Software
267
Freeware
It is a lowpass, highpass, bandpass, bandstop filter types designer.
Inear Display
17
Freeware
It is a Pre-Filter that offers you lowpass, highpass and bandpass modes.