RoveyDoveyGrovey
New Member
Hello,
Im having a nightmare with this I can't find the answer anywhere. Basically im looking for the formula to calculate the 3db point of a Bessel 3rd order sallen key filter. I need to test the circuit with various different component values, I just want a formula I can put into excel then easily calculate a number of different variations.
I know this,
1st order 3dB = 1/(2piRC)
2nd order 3dB = 1/(2pi*sqrtR1R2C1C2)
3rd order 3dB = ???????????????????????
I need to know the effect of component tolerances on the filter performance, any help would be very much appreciated, there's a picture of the circuit attached.
Im having a nightmare with this I can't find the answer anywhere. Basically im looking for the formula to calculate the 3db point of a Bessel 3rd order sallen key filter. I need to test the circuit with various different component values, I just want a formula I can put into excel then easily calculate a number of different variations.
I know this,
1st order 3dB = 1/(2piRC)
2nd order 3dB = 1/(2pi*sqrtR1R2C1C2)
3rd order 3dB = ???????????????????????
I need to know the effect of component tolerances on the filter performance, any help would be very much appreciated, there's a picture of the circuit attached.