a – DSB. Write the code for anm-file (script) to generate a DSB signal. The modulating (message)signal is a single tone signal with frequency 1kHz and the carrierfrequency is 30kHz. Time Vector: 3001 points over range from 0 to3ms (3 cycles of the modulating signal). Plot your original messagesignal both in time and its spectrum. (Note: the Matlab examples6.1 and 6.2 will help, but use the cosine functions for yoursignals instead of sine as in the example). In your report youshould include the plots for the modulated signal in time and forthe spectrum of the modulated signal.

b – AM. For the same messagesignal and same carrier as in part a. write the code for an m-fileto generate an AM signal. Do simulations for the followingpercentages of modulation: 1. 25% 2. 50% 3. 100% and 4. 125%. Inyour report you should include the plots for the modulated signalin time and for the spectrum of the modulated signal for each ofthe 4 cases. Discuss the results relative to the modulation indexm.

c – SSB. Use Matlab toimplement a 4 pole-pair Butterworth band-pass filter to select thelower frequency component of the DSB modulated signal in part a.Plot the signal at the output of the filter in time and itsspectrum. (Example 5.1 should be of help).

Part 2. Demodulation

For each of the signals generated in Part 1 in this second partdemodulation scheme should be implemented. (Hint: it mightbe better to implement demodulation right after the modulationsince you want to use the modulated signal of part 1 as yourinitial signal of part 2.) For demodulation you need first tomultiply the modulated signal of part 1. (which is considered nowto be the received signal assuming no noise was added and no otherdegradation of the signal happened during transmission = idealchannel) with the carrier. It might help to do the handcalculations too, to know exactly what to expect from yoursimulations. Use a Butterworth low-pass filter of your choice toselect the desired component. You should recover this way youroriginal modulating signal (eventually scaled in amplitude). For AMcase do the demodulation part only for case 2, m=0.5.