4.2-5 You are asked to design a DSB-SC modulator to generate a modulated signal km(t) cos wct with the carrier frequency fe = 300 kHz (we = 21 x 300, 000). The following equipment is available in the stock room: (i) a signal generator of frequency 100 kHz; (ii) a ring modulator, (ii) a bandpass filter tuned to 300 kHz. (a) Show how you can generate the desired signal. (b) If the output of the modulator is k - m(t) cos wd, find k.