LTSPICE Active filter simulation example
fn=4kHz, Q=10, Fliege type Band-Elimination-Filter

The transfer function of the band eliminate filter circuit shown above is,

To make the natural frequency ωn simple, we set
C1 = C2 = C0,
R1 =
R2 =
R3 =
R4 = R0
To make the second-order transfer function a band-eliminate-filter, i.e. to eliminate the second term in the denominator,
we set
R5
= R6
= RQ
Then with Q that is the quality factor, we have
1 / ω0 = C0 R0
ω0 / Q = C0 RQ
So Q will be
Q = RQ / R0
See Also



© 2000 Takayuki HOSODA.