See my article at: http://www.karlquist.com/FCS96.pdf
Toward the end I show some cascaded ceramic filters.
You can't necessarily just cascade them directly. Of
course it would be ideal to have buffer amplifiers in
between stages, complete with impedance transforming
stages, since the filters usually don't work with 50 ohm
terminations. However, as you can see in the article,
there are shortcuts.

Rick N6RK
www.karlquist.com
www.n6rk.com

"Tom Holden" wrote in message
. ..
I found some old postings that did not go into the how-to of cascading
cheap
ceramic filters in order to improve selectivity. I have a few 4-element
and
6-element 455kHz filters with which I am experimenting in an IF
downconverter for sound card DSP, specifically for DRM decoding which
requires a nice flat 10kHz bandwidth. I'm wondering if it is not a good
idea to DC couple them directly back-to-back. Should they be AC coupled?
Should there be a terminating resistor to ground or a T-pad at the
junction
to provide a more uniform load/source impedance? Or is it best to make up
for the losses and provide the proper terms by putting an active stage
between them than having the gain makeup before or after?

TIA,
Tom