In Fig. P4.2-6, if (t) = sin (wet + 0), and the output eo(t) is passed through a low-pass filter, then show that this circuit can be used as a phase detector, that is, a circuit that measures the phase difference between two sinusoids of the same frequency (wc). Hint: Show that the filter output is a de signal proportional to sin 6. Figure P.4.2-6 + (1) A cos a,! R -Slope R (a) (b)