4.2-4 You are asked to design aDSB-SC modulator to generate a modulated signal km(t) cos (@ct+0), where m(t) is a signal band-limited to BHz. Figure P4.2-4 shows a DSB-SC modulator available in the stock room. The carrier generator available generates not cos aet, but cos wct. Explain whether you would be able to generate the desired signal using only this equipment. You may use any kind of filter you like. (a) What kind of filter is rquired in Fig. P4.2-3? (b) Determine the signal spectra at points b and e, and indicate the frequency bands occupied by these spectra. (c) What is the minimum usable value of w? (d) Would this scheme work if the carrier generator output were sin wcr? Explain. () Would this scheme work if the carrier generator output were cos" wet for any integer n 2 2? Figure P.4.2-4 | M(S) m(t) km(t) cos w! Filter cos wt --B B (a)