SolderSmoke Daily News
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Putting a Ceramic Filter in the "Mate for the Mighty Midget" Receiver
Posted: 25 Oct 2021 03:55 AM PDT
http://soldersmoke.blogspot.com/2021/10/putting-ceramic-filter-in-mate-for.html
It is really simple. I had one of the +/- 3kHz (6 kHz wide) 455HT filters
on hand. The spec sheets call for 2000 ohms at both ends, but looking at
the schematic it appeared that I already had high impedance on both sides
of the filter. I put a .001 uF cap on the input side to keep the DC
voltage off the filter (see above and below). This capacitor allows us to
avoid the dreaded problem of