7. Derive the power spectral density of a. Polar non-return to zero coding b. Unipolar return to zero coding Starting with where we left off in class: _|P(), S, (f)= -ReJ2nfT T 8. Use delta modulation to quantize the signal below, with sampling rate of 0.01 and step size (delta) equal to 1 square. a. Show which bits should be transmitted for this signal. b. Identify where you see granularity noise and slope overload error by circling and labeling in the picture. 0.025 0.05 0.075 t (sec)