Contaminate an EMG with 50 Hz signal

I am trying to add a 50 Hz sinusoidal signal to an EMG signal but it isn't working. The amplitude of the 50 Hz signal should be 5% of the EMG signal amplitude. Can you give me with some tips on how to do it? I wrote the 50 Hz contamination like this: y = 0.005.*sin(2.*pi.*Fc.*t),

Thank you very much!

Answer 1

[Star Strider]

I have no idea what ‘isn’t working’ means.

This version of your code works:

Fs = 256;                                           % Create Sampling Frequency (Hz)
Ts = 1/Fs;                                          % Sampling Interval (sec)
t = 0 : Ts : 10;                                    % Define Time Vector
Fc = 50;                                            % Sine Curve Frequency
EMGRMS = 0.001;                                     % EMG RMS Amplitude (V)
MainsNoise = EMGRMS * 0.05 * sin(2*pi*Fc*t);        % Noise Vector

figure
plot(t, MainsNoise)
grid
xlim([0 0.1])

Note the additional detail. If you calculated it correctly, there should be five peaks in the plot (restricted to the first 100 ms).

I simply made up a value for the RMS amplitude. Note that to calculate the RMS amplitude (as I would have here if I had the signal), do this:

EMGRMS = sqrt(mean(EMG.^2));

where ‘EMG’ is your EMG signal vector.

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