MATLAB: Vectors must be the same lengths.

vectors

Hi guys I am trying to add a white Gaussian noise to FM signal

this is my code fc = 20; %Carrier Frequency fs = 1000; %Signal Frequency t = 0:0.00001:0.002; x = 2*cos(2*pi*t)-3*sin(2*pi*2*t); dev = 50; y = fmmod(x,fc,fs,dev); r = awgn(x,10,'measured'); plot(t,[y r]) legend('Original Signal','Signal with AWGN')

but i got this error "Vectors must be the same lengths".

can you help me ?

Best Answer

Try this instead:

plot(t,[y; r])

The (;) creates a (2xN) matrix that plot will accept.

Related Solutions

MATLAB: Generate Specific noise(i.e. 60 or 70 Hz) Matlab

If you just want to add a specific frequency noise in you signal then try this

f = 5;
fn = 60;
t = linspace(0, 1, 200);
y = sin(2*pi*f*t);
yn = 0.2*sin(2*pi*fn*t);
y = y + yn;
plot(t, y)

Check the fft() of the signal and you will see peaks at 5Hz (original signal) and 60Hz (noise)

Fs = 1/(t(2)-t(1));
fv = linspace(0, 1, numel(t))*Fs;
mag = abs(fft(y));
plot(fv, mag);

MATLAB: Ifft after one fft

The DFT and inverse DFT are mappings from a N-dimensional complex vector space to an N-dimensional complex vector space.

When you change N as you do by padding, then they are different, so you cannot expect the vectors to be the same.

What you can do is this:

spectreFFT2 = fft(y,pts);
y2 = ifft(spectreFFT2);
y2 = y2(1:length(y));
figure (2);plot(t,y,'b',t,y2,'r');

Since padding is just appending zeros, you simply remove the zeros at the end.

Best Answer

Related Solutions

MATLAB: Generate Specific noise(i.e. 60 or 70 Hz) Matlab

MATLAB: Ifft after one fft

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