M
Mike
- Jan 1, 1970
- 0
I think you still have a sign error; the amplifier has a gain of k,
not -k, and with the caps shorted, Vo/Vi is k
Ugh. You're right, and that's what was obvious by inspection. I even proved
that in my notes before posting:
Vo| -kc1c2c3
--| = -------------------------------------------------------
Vi|s->inf c1c3^2 + c2c3^2 + c2^2c3 - c3(c1c2 + c2^2 + c1c3 + c2c3)
which reduces to
Vo| -kc1c2c3
--| = --------- = k
Vi|s->inf -c1c2c3
I must have sign dyslexia. After posting that the gain is -k, I went one
step further and factored the equation with unity component values in
Mathcad. The result Mathcad produced was
-s^3
--------------------
-s^3 - 4s^2 - 4s - 1
Which I dutifully transcribed, switching the signs of the denominator
coefficients as I did so, while leaving the numerator untouched.
Let's see... if I make one more sign error, I'll be up to four, and they'll
all cancel out...
-- Mike --