5.4-2 A periodic square wave m(t) (Fig. P5.4-2a) frequency-modulates a carrier of frequency fe = 10 kHz with Af = 1 kHz. The carrier amplitude is A The resulting FM signal is demodulated, as shown in Fig. P5.4-2b by the method discussed in Sec. 5.4 (Fig. S.12). Sketch the waveforms at points b, c, d, and e. Figure P.5.4-2 m(t) (a) m(t) FM Envelope detector De modulator dt blocking Demodulator (b)