In Section 8.2.2, we discussed the use of an envelope detector for asynchronous demodula...

In Section 8.2.2, we discussed the use of an envelope detector for asynchronous demodulation of an AM signal of the form An alternative demodulation system, which also does not require phase synchroniza-tion, but does require frequency synchronization, is shown in block diagram form in Figure P8.26. The lowpass filters both have a cutoff frequency of . The signal , with , constant but unknown. The signal x(t) is band limited with , and with . As we required for the use of the envelope detector, x(t) + A > 0 for all t.