50. A signal x(t) = = sinc (150nt) is sampled at a rate of a) 100 Hz, b) 200 Hz, and c) 300Hz. For each of these cases, explain if you can recover the signal x(t) from the sampled signal.

10

Q3) A-Suppose that an analog signal is given as x(t) = 5cos (2 x 10³t) and is sampled at the rate 8kHz. Sketch the spectrum for the original signal and the sampled signal from 0 to 20kHz.

Q2- Explain by equations and block diagram the direct method demodulation in NBFM Q3- Write the formula of the phase modulation (PM) when Ac=25 , Fc=10® Hz, Kp= 20 . If an information signal m(t) = cos(212000t) + 10sin(2n2000t) Q4- Drive a formula for NBFM by using Bessel function Q5- If an information signal X(t) = cos(2n700t) + 10cos(25000t). Write the formula of the frequency modulation (FM) when Ac=20 , Fc=10® Hz, Kf= n2000 Q6-) If NBFM signal passes through a frequency multiplier. With B < 0.5 and fc=200kHz. Let fm ranges from 50OHZ to 15kHz, and let the maximum frequency deviation Afat the output be 75kHz. Find the required frequency multiplication n and the maximum allowed frequency deviation at the input. Q7- If an angle modulated signal S(t) = 10[cos(210®t) + 15sin(2n10³t)]