Hello everyone,
I need some help with the circuit below. Im trying to create a phase shift oscillator but i get nothing at the output or if i start fiddling with the gain on the last stage it just saturates. Im aiming for a frequency of 900 Hz.

I know w = (sqrt(3)) / RC
Where R is 30.63KOhms and C = 0.01uF

I also know the gain on the final stage must be 8, which I have. (i have also adjusted for a gain slightly higher then 8)

The loop gain is 1 and the overall phsae shift is 0. (60 + 60 + 60 - 180 = 0)

Does anyone notice anything im doing wrong, I have been at this for awhile.
Any suggestions are greatly appreciated,
Kind Regards.

 

The output from U4 is a saturated squarewave.
The output from U2 is a good sinewave and its output can be amplified if you want.

 

it turns out the circuit was fine... i just needed to let the simulation run for about 60 seconds before i was able to obtain the clean sine wave.