Pure tones or sinusoids are not very interesting to listen to. Modulation and other techniques are used to generate more interesting sounds. Chirps, which are sinusoids with time-varying frequency, are some of those more interesting sounds. For instance, the following is a chirp signal

y(t) = A cos(Ω_ct + s(t))

(a) Let A = 1, ­Ω_c = 2, and s(t) = t²/4. Use MATLAB to plot this signal for 0 ≤ t ≤ 40 sec in steps of 0.05 sec. Use sound to listen to the signal.

(b) Let A = 1, ­Ω_c = 2, and s(t) = −2 sin(t) use MATLAB to plot this signal for 0 ≤ t ≤ 40 sec in steps of 0.05 sec. Use sound to listen to the signal.