4.2-6 Amplitude modulators and demodulators can also be built without using multipliers. In Fig. P4.2- 6, the input (t)=m(t), and the amplitude A >l(t). The two diodes are identical, with a resistance of r ohms in the conducting mode and infinite resistance in the cutoff mode. Show that the output eo (!) is given by eo(t) = w(t) m(t) 2R R+r where w(t) is the switching periodic signal shown in Fig. 2.20a with period 2x/We seconds. (a) Hence, show that this circuit can be used as a DSB-SC modulator. (b) How would you use this circuit as a synchronous demodulator for DSB-SC signals. $(1) A cos mel R Φ(1) eo(t) $(t) R (a) -Slope- (b) Vd