<p>I wanted to calculate the ratio of Theta/Beta ($\Theta$/$\beta$) in decibels for a couple of electrodes in AF3 AF4 and Cz</p>

<p>I was able to get these in microvolts, but would like to convert them to decibels but am unsure what is the appropriate way to do so.</p>

<p>For instance, should I convert it like:</p>

<p>$$ratio_1 = 10.log\left( \frac{\Theta_{AF3} + \Theta_{AF4} + \Theta_{Cz}}{\beta_{AF3} + \beta_{AF4} + \beta_{Cz}}\right)$$</p>

<p>or</p>

<p>$$ratio_2 = 10.log\left(\frac{\Theta_{AF3}}{\beta_{AF3}}\right) + 10.log\left(\frac{\Theta_{AF4}}{\beta_{AF4}}\right) + 10.log\left(\frac{\Theta_{Cz}}{\beta_{Cz}}\right)$$</p>

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2017-12-02T06:07:04.207Z
Are you calculating the ratio of all electrode simultaneously?
If yes, i think the second one is correct.
maia
<measurement><eeg><signal-processing>
How do I measure ratio of EEG frequency band for a few electrodes in decibels?
Saldeho
# How do I measure ratio of EEG frequency band for a few electrodes in decibels?

(Asked by: username_0 on 2017-08-27)

I wanted to calculate the ratio of Theta/Beta ($\Theta$/$\beta$) in decibels for a couple of electrodes in AF3 AF4 and Cz

I was able to get these in microvolts, but would like to convert them to decibels but am unsure what is the appropriate way to do so.

For instance, should I convert it like:

$$ratio\_1 = 10.log\left( \frac{\Theta\_{AF3} + \Theta\_{AF4} + \Theta\_{Cz}}{\beta\_{AF3} + \beta\_{AF4} + \beta\_{Cz}}\right)$$

or

$$ratio\_2 = 10.log\left(\frac{\Theta\_{AF3}}{\beta\_{AF3}}\right) + 10.log\left(\frac{\Theta\_{AF4}}{\beta\_{AF4}}\right) + 10.log\left(\frac{\Theta\_{Cz}}{\beta\_{Cz}}\right)$$

**Tags:** measurement, eeg, signal-processing

> **Comments:**
> **username_1**: Are you calculating the ratio of all electrode simultaneously? If yes, i think the second one is correct.  

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## 0 answers

