Search found 6 matches

by giraffepigcat
Mon Jun 07, 2021 10:02 pm
Forum: Mind Monitor
Topic: Understanding the unit of measurement used on the Chart
Replies: 18
Views: 7426

Re: Understanding the unit of measurement used on the Chart

I see. Thank you so much for quick responses, James!
by giraffepigcat
Mon Jun 07, 2021 9:51 pm
Forum: Mind Monitor
Topic: Understanding the unit of measurement used on the Chart
Replies: 18
Views: 7426

Re: Understanding the unit of measurement used on the Chart

Got it, thank you.
I have something else to ask. What for is low_freqs (2.5-6.1Hz) is recorded? It overlaps with part of Delta and Theta.

low_freqs 2.5-6.1Hz
delta_absolute 1-4Hz
theta_absolute 4-8Hz
alpha_absolute 7.5-13Hz
beta_absolute 13-30Hz
gamma_absolute 30-44Hz
by giraffepigcat
Mon Jun 07, 2021 9:34 pm
Forum: Mind Monitor
Topic: Understanding the unit of measurement used on the Chart
Replies: 18
Views: 7426

Re: Understanding the unit of measurement used on the Chart

Sorry that I was confusing you, James.

I meant absolute brainwaves in dB. And dB is a (relative) unit-----(dB) = 10 log(P1/P0).
I wanted to know is there some process to get PSD of each waveband converted into dB?
by giraffepigcat
Mon Jun 07, 2021 9:16 pm
Forum: Mind Monitor
Topic: Understanding the unit of measurement used on the Chart
Replies: 18
Views: 7426

Re: Understanding the unit of measurement used on the Chart

James, The math is too hard for me :o But I would try to get it. :geek: By just now I saw FTT works on how to split out different wavebands by frequency and make sure the energy remains the same. As for PSD, it indicates the intensity or chance of wave frequency. Maybe I did not know if I was thinki...
by giraffepigcat
Mon Jun 07, 2021 8:19 pm
Forum: Mind Monitor
Topic: Understanding the unit of measurement used on the Chart
Replies: 18
Views: 7426

Re: Understanding the unit of measurement used on the Chart

Thank you again, James! :) I just got dB or Bel is a unit that measures the ratio of the quantity of two identical units, say P1 and P0 ---> take log. Asuming that P1 is for the brainwaves bands we are watching, i.e, Delta, Theta, Alpha, Beta, or Gamma, may I ask where is P0 from? Is P0 from low_fre...
by giraffepigcat
Mon Jun 07, 2021 4:03 am
Forum: Mind Monitor
Topic: Understanding the unit of measurement used on the Chart
Replies: 18
Views: 7426

Re: Understanding the unit of measurement used on the Chart

Hi James, Thank you so much for the app and website! And I'm looking through the issues concerning scales and units of measurements. 1. The absolute band power for a given frequency range (for instance, alpha, i.e. 9-13Hz) is the logarithm of the sum of the Power Spectral Density of the EEG data ove...