Frequency modulation


y = fmmod(x,Fc,Fs,freqdev)
y = fmmod(x,Fc,Fs,freqdev,ini_phase)


y = fmmod(x,Fc,Fs,freqdev) modulates the message signal x using frequency modulation. The carrier signal has frequency Fc (Hz) and sampling rate Fs (Hz), where Fs must be at least 2*Fc. The freqdev argument is the frequency deviation constant (Hz) of the modulated signal.

y = fmmod(x,Fc,Fs,freqdev,ini_phase) specifies the initial phase of the modulated signal, in radians.


The code below modulates a multichannel signal using fmmod and demodulates it using fmdemod.

Fs = 8000; % Sampling rate of signal
Fc = 3000; % Carrier frequency
t = [0:Fs-1]'/Fs; % Sampling times
s1 = sin(2*pi*300*t)+2*sin(2*pi*600*t); % Channel 1
s2 = sin(2*pi*150*t)+2*sin(2*pi*900*t); % Channel 2
x = [s1,s2]; % Two-channel signal
dev = 50; % Frequency deviation in modulated signal
y = fmmod(x,Fc,Fs,dev); % Modulate both channels.
z = fmdemod(y,Fc,Fs,dev); % Demodulate both channels.

See Also

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