Mind Monitor

For FFT most of the time you will get exactly the same results as James pointed out, but there could be some caveats. For example, the FFT points (usually 2^n) can affect the results. You may perform FFT simply as y = fft(x), or as y = fft(x, 2^n) for different n's, then you will get different resul...

Hi Peter, yes, Matlab is very expensive but GNU Octave (https://www.gnu.org/software/octave/) is free, and it is 95% interchangeable with Matlab.

GNU Octave (https://www.gnu.org/software/octave/) is 95% interchangeable with Matlab. FFT and related functions are included in Octave. At least when your data is a 1D array, the FFT is quite straightforward to perform.

It will be very useful to stream the other sensor data. My guess is that we can first apply a low-pass filter to remove some high-frequency noise. Then apply some kind of Fourier transform to convert the data from time-domain to frequency-domain and read out the frequency of the pulse. It could be t...

Oscar, I was wondering about the same thing. Technically, for PSD with input signals in μV, the unit is μV^2/Hz, and we typically convert that to dBμV/Hz by doing 10*log10(PSD). However Interaxon said it's Bel so I guess they only did log10(PSD), which is not quite common. If we multiply their value...

Yeah that's what I tried, but somehow the results are not the same. The averaging/filtering in the log domain will be different from the log of the averaging/filtering in the linear domain. Anyway, both make some senses, though.

Thanks. I found the "recording interval" "Constant" option and just did a 20 min session. The zip file is about 8 MB, and after unzip it is about 126 MB :) Yes only the raw data changes for every row and others are repeated for multiple rows which helps compress the files. Actual...

I used that formula to compute the relative power percentages but got different numbers from your online graph. Did you do yours before the filtering/averaging or after the filtering/averaging? These values are not in the csv file so we have to compute them from the absolute eeg data. Also we cannot...

Very helpful. Thank you

I got your point. Thank you.
Then how did you compute the relative fraction for each type? Did you sum up the values directly or convert them from the log domain back to linear domain (10^value) and then sum up?