Il 01/01/2011 3.36, Joel Koltner ha scritto:
I'm designing an IF filter for a receiver that's placed at the output of
a passive (diode-type) mixer. While the mixer's RF input is being fed
with a (nominally) 50ohm source, is it correct to think that "looking"
back into the IF port the filter is going to "see" a 50ohm impedance as
well? (Normally I'd have a buffer stage right after the mixer to
re-establish impedance levels, but in this case I'm trying to keep
things low-power and hence directly feed the mixer's output into the
filter.)

Thanks,
---Joel


Yes,but only if the other two ports are closed with 50 ohm...

Happy new year,

Piero.

P.S: Beware of filters, they are highly reactive outside their
resonant frequency, so (they) reflect back signals with
worsening behaviour of mixer ( spurs ).
P.