In small-signal operation the diode-bridge arrangement of Fig. P1.68 allows for direct signal coupling between vi and vo, without the need for any ac-coupling capacitor. It also relaxes the...

In small-signal operation the diode-bridge arrangement of Fig. P1.68 allows for direct signal coupling between vi and vo, without the need for any ac-coupling capacitor. It also relaxes the small-signal constraint. The increased circuit complexity is well worth these advantages, especially in integrated-circuit implementations, where large capacitances are impractical. (a) Show that in small-signal operation, the diode bridge acts as a single current-controlled resistance r 5 2VTyI. (b) Show that the small-signal constraint of Eq. (1.82) is now more relaxed and becomes uvou # 10 mV. (c) If R 5 10 kV and vi 5 (1.0 V) cos t, fi nd I for vo 5 (10 mV) cos t.