Larry N2AJX Wrote ¡°I swept the crystal filter and found its 3dB bandwith at only 1.2 kHz, less than half of what it should be. So I experimented a little and found that by changing the 5 capacitors from the crystals to ground from 100 pF each to 82 pF each, the bandwidth increased to 2.4 kHz¡±
(sorry for the size change with
Pasting)
On uBitx.net under Crystal Experimentation it says
¡±
3) As suggested by Allison KB1GMX, 82pF is working just fine in the filter and achieves a bandwidth of around 2.2Khz. Capacitor value is bit touchy between 82 to 100pf.
4) The Q of capacitors used has a major impact on the filter response. Parallelling up two values to arrive at a desired overall capacitance value results in a better response.¡±
so
do we want hi or low Q?
how is the ¡°response¡± better?
does paralleling capacitors increase or lower the Q?
what does ¡°touchy¡±mean when talking about values between 82 and 100pF?
Thanks!
For ever clueless,
jer aa1of
(really, I do much better if you spell it out...)
