Notch
to BPF conversion
Designed by sv3ora
Here is a simple method in which a notch
filter can be converted to a BPF using the phasing inversion method. I
do not know why one would want to do it like this, but in theory it
should have some interesting properties. It should in theory have zero
insertion loss (depended on the loss and flatness of the active
circuits and the phasing process however). It is also different in the
sense that the out of notch frequencies are completely canceled at the
end, not just attenuated as in the case of a peaking filter. Notch
filters can be easily made with a series shunt LC, with the variable C
grounded, so no hands effects or insulation from the chassis is
required. They can be bypassed on TX with a single spst switch. They
can be easily cascaded without affecting the insertion loss in the
pass-band. Another advantage is that with the flip of the switch, one
can have both a BPF and a NOTCH without extra LC circuits.
Back to main
site