Microvolts to frequency

[Navaneeth.A.Gowda]

We are doing project on EEG signals using OpenBCI device, output of signals are in microvolts how can we convert them to Frequency ?

 

[KlausST]

Hi,

amplify the signals, then feed it to VFC or VCO.

Klaus

 

[Navaneeth.A.Gowda]

Thank you sir, is there any python package For VFC or VCO

 

[KlausST]

Hi,

Python as language?
Amplifier and VFC / VCO all are hardware, no need for software.

Klaus

 

[wwfeldman]

forgive my curiosity
why are you converting from voltage to frequency?

 

[danadakk]

Some questions -

1) What is the range of signal, min to max, of signal you want to convert to frequency ?

2) For the range in 1) above what is range of frequencies you want ?

3) What is resolution of signal you want, both in 1) and 2) ?

4) Do you want a sine, square, encoded frequency signal out of solution ?

5) Do you need to filter signal path ? LPF, BPF, HPF, Band Reject (to get rid of power line freq 50/60 Hz)....?

Regards, Dana.

 

[Navaneeth.A.Gowda]

forgive my curiosity
why are you converting from voltage to frequency?

Bcz all the brain signals like alpha,beta etc are measured under Frequency.

 

[betwixt]

So you don't want to convert them to frequency, you want to measure their frequency?

Brian.

 

[Navaneeth.A.Gowda]

So you don't want to convert them to frequency, you want to measure their frequency?

Brian.

Yes, i have values from -15000 micro volts to 15000 micro volts EEG data. i want these values in frequencies ranging from 0 to 100 hz. What are the steps i need to follow? Could you help me, in what order to follow the steps

 

[Navaneeth.A.Gowda]

Some questions -

1) What is the range of signal, min to max, of signal you want to convert to frequency ?

2) For the range in 1) above what is range of frequencies you want ?

3) What is resolution of signal you want, both in 1) and 2) ?

4) Do you want a sine, square, encoded frequency signal out of solution ?

5) Do you need to filter signal path ? LPF, BPF, HPF, Band Reject (to get rid of power line freq 50/60 Hz)....?

Regards, Dana.

I have values from -15000 micro volts to 15000 micro volts EEG data. I want these values in frequencies ranging from 0 to 100 hz bcz brain signals are measured in terms of Hertz, What are the steps i need to follow? Could you help me, in what order to follow the steps

 

[FvM]

The required procedure is calculating the power spectrum, respectively magnitude of fourier transform. As far as I see, it's already included in OpenBCI software tools. Did you read the manual?

See FFT Plot below:

 

[Navaneeth.A.Gowda]

The required procedure is calculating the power spectrum, respectively magnitude of fourier transform. As far as I see, it's already included in OpenBCI software tools. Did you read the manual?

See FFT Plot below:

View attachment 170274

The data I have is completely raw, this raw file contains only values in microvolts

 

[danadakk]

Your sample set is directly applicable to handling with FFT. It will produce
the spectrum of the magnitude for each frequency contained in the sample
set you have. This is a translation of |f(t)| (your sample set) to power spectra.

http://stackoverflow.com/questions/...-fft-when-doing-spectral-analysis-of-a-signal UNITS

http://www.sjsu.edu/people/burford.furman/docs/me120/FFT_tutorial_NI.pdf

http://papers.vibetech.com/Paper09-FundamentalsOfTheDFT.pdf

Regards, Dana.

 

[FvM]

If you don't use OpenBCI software for spectrum calculation, Matlab or Octave can do.