Hi,

As part of a university project i would like to build an active 4th order filter. Using analog devices filter wizard i can design a MFB bandpass filter with the calculated component values . However from a learning point of view i would like to know the formulas of how they were determined.

on the internet there are plenty of websites listing the equations for a single opamp 2nd order filter, however i have not come across any equations for a 2 opamp 4th order filter.

any one have any idea why i can find some information on calculating these equations

 

This might help.

 

Hello,

Have a look at chapter 16 of the following PDF for all kinds of active filter topics:
slod006b Op Amps For Everyone.pdf

Bertus