I'm trying to figure out how to calculate the gain and input impedance of a certain amplifier circuit that has two stages of feedback. Basically it's a two-stage amplifier that has voltage-sampling series feedback from the output into the emitter of the first stage, and then has a current-sensing resistor that does shunt mixing into the base of the first stage. \(\beta\) for the voltage sampling series feedback stage is going to be the ratio of the feedback voltage to the output voltage, and \(\beta\) for the current-sampling shunt mixing stage is going to be the ratio of the feedback current to the output current. Those ratios are easy enough to find, but what I'm not sure about is how to apply the standard feedback equation \(\frac{A}{1+A\beta}\). Would the gain just be derived using the sum of the two betas? In this case the series mixing stage is trying to raise the input impedance, while the shunt mixing stage is trying to lower it. Does one calculate the rise and the fall independently, and then sum the result? Thanks for any advice.