% Frequency Modulation:
close all
syms A t wm fs kf kp wc A1 % Constucted variables to integrate the
message signal for FM
m = A1*cos(wm*t) % Message Signal
i = int(m,t) % Integrated Signal
% Arguments:
t = 0:0.002:2; % Time vector with values 0 to 2, taking 1000
samples
A = 1; % Amplitude of both message signal and of the
expression of FM and PM
wm = 2*pi*0.5; % Frequency of message signal
fs = 500; % Sampling rate
kf = pi/4; % Constant
kp = pi/3; % Constant
wc = 2*pi*10; % Frequency of carrier signal
A1 = 10; % Amplitude of message signal
% After giving values:
m = A1*cos(wm*t);
i = A1/wm*sin(wm*t);
% Time Domain:
phiFM = A*cos((wc*t)+(kf*i));
phiPM = A*cos((wc*t)+(kp*m));
figure, plot(t,m), title('Original
Signal'),xlabel('time'),ylabel('Amplitude')
figure, plot(t,phiFM), title('Frequency Modulated
Signal'),xlabel('time'),ylabel('Amplitude')
figure, plot(t,phiPM), title('Phase Modulated
Signal'),xlabel('time'),ylabel('Amplitude')
% Frequency Domain:
w=-250:(2*250)/1000:250;
PHIFM = fftshift(abs(fft(phiFM)));
PHIPM = fftshift(abs(fft(phiPM)));
figure, stem(w,PHIFM), title('Fourier Transform of FM signal that shows
the frequencies produced'), xlabel('linear
frequency'),ylabel('Amplitude')
figure, stem(w,PHIPM), title('Fourier Transform of PM signal that shows
the frequencies produced'), xlabel('linear
frequency'),ylabel('Amplitude')
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