# \[MNE analysis\] psd\_welch **URL:** \ **Category:** Mailing List Archive (read-only)\ **Tags:** list-archive\ **Created:** [February 15, 2019, 2:38pm UTC](https://mne.discourse.group/t/mne-analysis-psd-welch/1744 "2019-02-15T14:38:24Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [February 15, 2019, 2:38pm UTC](https://mne.discourse.group/t/mne-analysis-psd-welch/1744/1 "2019-02-15T14:38:24Z")
External Email - Use Caution Dear MNE team, I have some doubts about the units psd\_welch returns for the PSD as my output values have a magnitude of 10\*\*-11/-12 and I'd like to get the same values in dB that are displayed in the plot when using: rawB0939\_copy.plot\_psd(fmin=0.5,fmax=30) Maximum values I get in the plot in the range of 0-4 Hz are around 15 to 25 dB, using the different dB (True/False) and estimation (auto,power,amplitude) options. I use this line of code to compute psd values: psd\_delta,freqs\_delta=time\_frequency.psd\_welch(rawB0939\_copy,fmin=0.5,fmax=4) Thank you for your help, Lidia ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [February 15, 2019, 3:04pm UTC](https://mne.discourse.group/t/mne-analysis-psd-welch/1744/2 "2019-02-15T15:04:57Z")
External Email - Use Caution Is it perhaps just a problem of units? The plotters typically scale things to show data in uV or fT, whereas data on disk (and thus returned by `psd_welch` et al.) are stored in the objects in SI units (V, T). Eric