How to Add random noise to a signal
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hello all
please can ou help me out adding a noise signal to my system.
i tried adding a sinus function , but i would like to add a random noise signal rather than the sinus function. I'm running simulation from 1 to 3000
if k>1000 & k<2000
dk(k)=sin(12*k*pi*ts);
x=A*x+B*u(k)+B*dk(k);
else
dk(k)=0;
x=A*x+B*u(k);
end
Thank you so much
Best regards
댓글 수: 2
Image Analyst
2020년 3월 14일
이동: DGM
2023년 3월 4일
What does that mean? Audio IS a signal. You can't add noise to audio without adding it to the signal that defines the audio waveform.
답변 (6개)
Thorsten
2015년 5월 20일
x = linspace(-2*pi, 2*pi);
plot(sin(x) + 0.5*rand(size(x)))
댓글 수: 5
Image Analyst
2020년 2월 12일
Tuhin, you can have the amplitude vary with the signal amplitude if you want. For example
% Create noise-only signal.
noisy_signal = rand(size(noise_free_signal));
% Create an amplitude for that noise that is 10% of the noise-free signal at every element.
amplitude = 0.1 * noise_free_signal;
% Now add the noise-only signal to your original noise-free signal to create a noisy signal.
% Be sure to use .*, not *, so that you do element-by-element multiplication.
noisy_signal = noise_free_signal + amplitude .* rand(size(noise_free_signal));
% Adjust amplitude to control the amount of noise.
Now the noise - the max possible noise amplitude - will vary according to the noise-free signal amplitude. Of course since it's noise, the noise won't always be the max possible, it will be less, but it could potentially get that high.
Tuhin Choudhury
2020년 3월 16일
편집: Tuhin Choudhury
2020년 3월 16일
Hi,
Thanks. This would be more of a flexible scaling of the noise w.r.t the input signal.
BR- Tuhin
Image Analyst
2015년 5월 20일
So just use rand() instead of sin().
댓글 수: 4
Prajakta Yeola
2017년 10월 29일
Can we use the same code if audio signal is .wav file? i.e. if x is a .wav file
Image Analyst
2017년 10월 29일
Sure, just figure out the amplitude and add it
yNoisy = yOriginal + amplitude * rand(1, length(yOriginal));
KL
2015년 5월 20일
댓글 수: 2
KL
2015년 5월 20일
There's a difference between wgn() and awgn(). With the latter, you add noise throughout the whole range. I understand you want to add noise between certain time intervals. So in this case, I would suggest to use wgn(). At the moment I do not have the toolbox to use this function. Anyhow you shall use this function to calculate the noiseSignal variable according to @Image Analyst's code.
Aparna Gupta
2017년 6월 21일
Can anyone please help me with the code to add awgn noise to an eeg signal,which i have taken from a database and the file is of .mat type?
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Mohammad Sohail Khan
2017년 11월 3일
편집: DGM
2023년 3월 4일
t = 0:pi/100:40;
x = cos(pi/10*t)+0.5*randn(size(t));
plot(t,x)
Then you know where pi/2, 3pi/4 etc are.
댓글 수: 0
Adewale Obaro
2018년 9월 24일
편집: DGM
2023년 3월 4일
N = 1000;
t = 0:1/N:2;
x = sin(2*pi*5*t);
Noise = x + randn(1,N)';
plot(t,Noise);
title('Noise in the Amplitude interval (0,0,1,0)');
ylabel('Amplitude [m]')
xlabel('Time [s]')
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