Spectral density, noise

I have loaded one row of data into variable EEG. I need to calculate spectral density and if 50HZ reaches noise of 5dB when compared to baseline, I need to execute a notch filter (already written). Can someone help me with calculating spectral density and how to check if noise is larger than 5dB at 50Hz?

Answer 1

[Image Analyst]

Call pwelch().

[Emoke Ipkovich]

Thank you. I have checked pwelch in Documentation but I did not find how I can check for larger than 5dB noise at 50Hz from the baseline. How do I provide 50 Hz and 5 dB as parameters to pwelch?

[Image Analyst]

What do you have that you consider "noisy signal" and what do you have that you consider "true signal" so that you can compare them by looking at the power in the 50 Hz range? Are you saying that absolutely anything at 50 Hz is pure noise?