Boy Jerry,
I got in too big a hurry, and I should not have said tee in the feedback path,
but in the INPUT path of an op amp to make up the gain loss of the Notch
Filter.
Even with a simple one FET preamp following, we got 60 dB notches in audio
band at single frequency, with tuning giving less. (40 dB).
Yes, you need two caps, and a resistor in one Tee and two resistors and a cap
in the other Tee leg, so that is three each.
The classic paper on twin tee applications was by Gifford White of White
Instrument Labs, right here in Austin, TX. That was sometime prior to 1963!
--
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Submissions: tentec@contesting.com
Administrative requests: tentec-REQUEST@contesting.com
Problems: owner-tentec@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|