# Adding EMG Signal With 50Hx Sinosoidal wave. Not getting it correct

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Amit jha on 17 Oct 2016
Commented: Christoph F. on 4 Nov 2016
Start Time =0.00025, time interval=0.00025 and end time=12.715
I have loaded emg signal of above specified time and adding it to 50Hz noise (sinosoidal Signal), but not getting it correctly, please reply
figure(1);
subplot(3,3,1);
plot(emg(:,1), emg(:,2));
title('original EMG Signal');
t=0.00025:0.00025:12.715;
freqNoise = 50;
amplNoise =0.0025;
myNoise = amplNoise.*sin(2*pi.*t.*freqNoise);
[a b]=size(emg);
myNoisetransp=transpose(myNoise);
[u v]=size(myNoisetransp)
for j=1:(b-v)
myNoisetransp(:,j+1)=0;
end
subplot(3,3,2);
plot(t,myNoise);
title('50HZ Sinosoidal PL Noise');
noisysig=emg+myNoisetransp;
subplot(3,3,3);
plot(t,noisysig);
title('EMG+PL Noise');
Graph is generated but sinosoidal wave is not overlapped with EMG Signal

Christoph F. on 17 Oct 2016
What is the scale of
emg(:,2)
myNoise may have a different scale than emg(:, 2) and become too small to display once the two signals are added.
##### 3 CommentsShow 1 older commentHide 1 older comment
Amit jha on 18 Oct 2016
this is the problem, when i am adding sinosoidal signal with emg signal, emg is separeted as green and sinosoidal as blue, Refer in figure titled EMG+PL Noise and help on basis of above code
Christoph F. on 4 Nov 2016
noisysig=emg+myNoisetransp;
plot(t,noisysig);
emg has (at least) two columns, with time information in the first column (emg(:, 1)) and voltage information in the second column (emg(:, 2)).
To add the generated noise to the emg voltage column, try
noisysig = emg(:, 2) + myNoisetransp;
(The jpg shows two vectors being plotted in the third graph: the emg voltage vector in green, and the time vector plus added noise in blue.)

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