# Characteristic impedance and transfer function

1. Feb 22, 2010

### ipmac

I have to find the absolute value of the transfer function for the circuit shown in the attachment. However, I have capacitors instead of inductors in my circuit and inductors instead of capacitors. So, the cross circuit will have L in the upper and lower branch and two C in the cross. I couldn't form the A-matrix of the two port circuit. Because of this the characteristic impedance couldn't be found and thus transfer function. Could you please enlighten me in this matter?

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• ###### cross circuit.png
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2. Feb 22, 2010

### Staff: Mentor

What equations would you write to start to work toward an equation for Vout = f(Vin)?

3. Feb 22, 2010

### ipmac

As far as my understanding, we first determine the characteristic impedance by computing the input impedances Zo(open) and Zs(short) in Laplace domain when terminating the other port with impedances infinity (open) and zero (short). The characteristic impedance follows squrt(Z0.Zs). This is one way to find the characteristic impedance but I am supposed to get with with the computation of A-matrix which I am quite not sure.