Use MATLAB and provide code and plots please. Consider the information bearing s

Question

Use MATLAB and provide code and plots please.

Consider the information bearing signal given in Exercise 2 m(t) = {sin c(100 t), -0.1 lessthanorequalto t lessthanorequalto 0.1 0, otherwise and the carrier signal c(t) = A_c cos (2 pi f_c t) where A_c = 1 and f_c = 250 Hz. Assume that the frequency deviation is f_delta = 100. Thus, the frequency modulated signal s(t) is written as s(t) = A_c cos (2 pi f_c t + 2 pi f_delta integral^t_0 m(tau) d tau) (a) Plot the frequency modulated signal s(t) and its amplitude spectrum |S(f)|. Use N_f = 2048, assume that t ranges from -1 to 1 and use increments of 0.001. (b) Demodulate signal s(t) (see Exercise 2, Computer Assignment VI). Plot the recovered signal m cap (t) and compare it with the original information bearing signal m(t). (c) Assume that the signal-to-noise-ratio (SNR) of the received signal at the detector's output is 16 dB. Calculate the noise power. (d) Plot the received signal r(t) = s(t) + n(t), where s(t) is the frequency modulated signal s(t) and n(t) is additive white gaussian noise with mean 0 and variance equal to the power calculated in question 4(c). (e) Repeat step (b), use a lowpass filter with cut-off frequency f_cut = W Hz, where W denotes the bandwidth of m(t), and compare the recovered signal m cap (t) with the noiseless case.

Explanation / Answer

Fs = input(‘enter the value of Fs ‘); % Sampling rate of signal
Fc = input(‘enter the value of Fc ‘); % Carrier frequency
t = [0:Fs]’/Fs; % Sampling times
x = sin(2*pi*20*t)%+2*sin(2*pi*60*t); % Channel
dev = input(‘enter the value of dev ‘);% Frequency deviation in modulated signal
y = fmmod(x,Fc,Fs,dev); % Modulate both channels.
n = input(‘enter the value of snr ‘);
n = awgn(x,30);
z = fmdemod(y,Fc,Fs,dev); % Demodulate both channels.
figure;
subplot(3,1,1);
plot(x);
subplot(3,1,2);
plot(y);
subplot(3,1,3);
plot(z);

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