Answer Happy

You are asked to design a DSB-SC modulator to generate a modulated (10 signal km(t)coswt), where m(t) is a signal band-limited to B Hz. Fig. 2 shows a DSB-SC modulator available to you as an engineer. The carrier generator available generates cos(Wet) instead of cos(Wet). Explain whether you would be able to generate the desired signal using only this equipment by using an appropriate filter? (You may use any kind of filter that you like.) Hint: Expand the input to the filter, i.e. the modulated signal m(t)cos” (Wet), as m(t)cos (w.t)(cos?(Wet)). (i) What kind of a filter is required in Fig. 2? (ii) If the modulating signal has the spectrum as in Fig. 3, determine the signal spectra after modulation with the carrier signal cos" (Wet) and at the output of the filter. m(t) Filter km(t) cos(wet) cos? (wct) Fig. 2. Available modulator. M(w) A Fig. 3. Spectrum of the modulating signal.