The circuit of Fig. P4.79, called current conveyor, fi nds application in fast current-signal processing. The circuit has two input terminals X and Y and one output terminal Z, and it is made up of...

The circuit of Fig. P4.79, called current conveyor, fi nds application in fast current-signal processing. The circuit has two input terminals X and Y and one output terminal Z, and it is made up of the ordinary pnp current mirror Q1-Q2 and the dualoutput npn current mirror Q3-Q4-Q5. (a) Describe circuit behavior by asking yourself what happens when the source iX is turned on. Hence, assuming negligible base currents, fi nd vX as a function of vY, and iY and iZ as functions of iX. (b) Obtain expressions for the small-signal resistances Rx, Ry, and Rz seen looking into the corresponding terminals.