How can i add to an noise to signal?

I have generated a code and implemented the database.

Answer 1

[Star Strider]

This will add normally-distributed broadband random noise to your EEG signal vector:

sd = 0.1;                                       % Standard Deviation Of Random Noise Vector
normal_noise = sd*randn(1, N);                  % Create Normally-Distributed Random Noise Vector With Standard Deviation = ‘sd’
noisy_EEGsig = EEGsig + normal_noise;           % Add Noise To ‘EEGsig’

[Aparna Gupta]

Thanks a lot @Star Strider.This was really helpful. The sd value can be altered as per our choices or it has to be kept as 0.1 always?

[Star Strider]

My pleasure. Thank you.

I defined ‘sd’ as 0.1 arbitrarily. You can define it to be any value. Experiment with it so that it gives you the amplitude of the noise you want, depending on the amplitude of your EEG. If your EEG is measured in millivolts, the 0.1 value could be appropriate. If your EEG is measured in volts, a value on the order of 0.0001 could be best.

[Aparna Gupta]

@Star Strider, my EEG is measured in uVolts.What value of sd can i use?

[Star Strider]

If your data are in microVolts and the conversion (multiplication by 1E+6) has already been done, then 0.1 is appropriate for ‘sd’. If your data are in Volts, then use a value on the order of 1E-7 for ‘sd’.

(I have not worked with EEG in a while, and forgot the units.)

[Aparna Gupta]

@Star Strider,Yu have helped in every possible way,thanks for the help :)

[Star Strider]

As always, my pleasure.