Twin-t notch filter transfer function

[miketan3904]

Hi. I am referring to this document: https://www.analog.com/media/en/training-seminars/tutorials/MT-225.pdf
I was trying to derive the transfer function given in the document but failed.

I have attached the schematic diagram with node labeling and the equation that i wrote at node Vx, Vy and the non-inverting input of U4. I substitute the first and second equation into the third equation but the transfer function that i get (fourth equation) is different from the document.

I would appreciate if someone can point out my mistake. Thank you!

[RoGeorge]

Last time you posted here https://www.eevblog.com/forum/beginners/input-impedance-of-twin-t-notch-filter/ and abandoned the subject.

To see if there are any answers to your own posts, click the "Show new replies to your posts." link shown in the upper left of any page in this forum, the link on the right of your avatar picture, under your own username.

[Benta]

From what I can see, no mistake. I'm sure you're in a position to work this out. Cut 'n paste doesn't do it.