I have the following circuit and wanted to find out the transfer function of the whole circuit (which includes the non-ideal op-amp as well – modelled as a VCVS – H(S) is DC gain with some poles).
I tried the following:
1-To model it as a simple Op-Amp with feedback network with the transfer function as shown below:
But with this, I could only model an opamp with a constant dc gain and with poles. But the Input capacitance and output resistance of opamp (non-idealities) are not included.
2-To include the non-idealities of the op-amp (input capacitance and output resistance), I tried to analyze with a different approach with the feedback network modelled as a Two-port network – something like below:
Somehow I got the h12,h11,h22 by solving the twin-T bridge (using Delta start transformation -> combining the parallel resistances -> then finding voltage gain, input and output resistances) using mathematica, but the relations got more complicated and it was of third order which I feel it was not correct.
I modelled the two-port network using h-parameters since it was a voltage-current feedback. But should i consider it as a different feedback structure (like a voltage-voltage feedback) and then try? or Is there any other method to get the whole transfer function?
Any help or guide in getting a simplified expression for the whole transfer function (with feedback and non-idealities) of the above circuit will be helpful.