1. a. For a baseband signal m(t) = cos wmt = cos 27 fmt, Find the DSB-SC signal and sketch its spectrum. Identify the USB and LSB. b. For each of the baseband signal: (i) sketch the spectrum m(t), (ii) sketch the spectrum of the DSB-SC signal m(t)cos 10,000nt, (iii) Identify the USB and LSB. (i) m(t) = cos 1000r t; (ii) m(t) (iii) m(t) = cos 10007 i cos 300071, с. You are asked to design a DSB-SC modulator to generate a modulated signal km(t) cos (wet+0), where m(t) is a signal band-limited to B Hz. Figure P4.2-4 shows a DSB-SC modulator available in the stock room. The carrier generator avaitable generates not cos wet, but cos³ wet. 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 required in Fig. P4.2-3? (b) Determine the signal spectra at points b and e, and indicate the frequency bands occupied by these spectra. MS) km(1) cos a, Filter cos ca (a) (b)