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
2 件のコメント
Image Analyst
2020 年 3 月 14 日
移動済み: DGM
2023 年 3 月 4 日
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.
回答 (6 件)
Thorsten
2015 年 5 月 20 日
x = linspace(-2*pi, 2*pi);
plot(sin(x) + 0.5*rand(size(x)))
5 件のコメント
Image Analyst
2020 年 2 月 12 日
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
2020 年 3 月 16 日
編集済み: Tuhin Choudhury
2020 年 3 月 16 日
Hi,
Thanks. This would be more of a flexible scaling of the noise w.r.t the input signal.
BR- Tuhin
Image Analyst
2015 年 5 月 20 日
So just use rand() instead of sin().
4 件のコメント
Prajakta Yeola
2017 年 10 月 29 日
Can we use the same code if audio signal is .wav file? i.e. if x is a .wav file
Image Analyst
2017 年 10 月 29 日
Sure, just figure out the amplitude and add it
yNoisy = yOriginal + amplitude * rand(1, length(yOriginal));
KL
2015 年 5 月 20 日
2 件のコメント
KL
2015 年 5 月 20 日
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
2017 年 6 月 21 日
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?
1 件のコメント
Mohammad Sohail Khan
2017 年 11 月 3 日
編集済み: DGM
2023 年 3 月 4 日
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.
0 件のコメント
Adewale Obaro
2018 年 9 月 24 日
編集済み: DGM
2023 年 3 月 4 日
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]')
0 件のコメント
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