adding noise to a wav file

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AngelsaAtWar
AngelsaAtWar 2013-3-27
评论： Walter Roberson 2018-3-31
if I add noise to the script...
load handel.mat;
hfile= 'handel.wav';
wavwrite(y, Fs, hfile);
nsamples=Fs;
[y, Fs , nbits, readinfo]= wavread(hfile,nsamples);
sound(y(round(2.85/4*end):end),Fs);
How would I do so, I know I need some kind of vector to do it but I dont know how to approach it

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采纳的回答

Walter Roberson
Walter Roberson 2013-3-27
y = y + randn(size(y));
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Walter Roberson
Walter Roberson 2013-3-27
Multiply randn() by a fraction, such as 1/10 or 1/100.
AngelsaAtWar
AngelsaAtWar 2013-3-27
It works, Thank you very much for the help. I really apprecite it

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更多回答（2 个）

Youssef Khmou
Youssef Khmou 2013-3-27
编辑：Youssef Khmou 2013-3-27
hi,
You have many ways :
1) method one :
Mean=0.00;
Var=0.005;
z=imnoise(y,'Gaussian',Mean,Var);
You can control the amount of noise to add, with N(mean,variance ), and also you can change the type of noise you want ' Poisson','speckle'.....
2)method two :
SNR=15;
z=awgn(y,SNR,'measured');
With awgn stands for Additive white Gaussian noise, u work here in terms of Signal to Noise Ratio with SNR=20 log10( signal_power/ noise_power ).
3) method three :
Like Walter answer :
STD=sqrt(0.005); % STANDARD DEVIATION
z=y+STD*randn(size(y))
z=y+randn(size(y)) ; % Means adding Zero mean noise and VAR=1 .
  1 个评论
Youssef Khmou
Youssef Khmou 2013-3-27
example, i prefer working with SNR :
load handel.mat
Y=y(round(2/3*end:end));
SNR=11; % dB
Z=awgn(Y,SNR,'measured');
figure, plot(Z), hold, plot(Y,'r'), legend('AWGN snr=11dB',' Clean Signal')

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tayyab awan
tayyab awan 2018-3-31
How to remove this noise in order to retrieve the original signal ??
  1 个评论
Walter Roberson
Walter Roberson 2018-3-31
There have been a number of Questions dealing with noise removal; you should do a search.

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