| POP_SNAPREAD | Load an EEG SnapMaster file (pop out window if no arguments). |
| Usage: | >> [dat] = pop_snapread( filename, gain); |
| Graphic interface: | |
"Relative gain" |
[edit box] to compute the relative gain, fisrt look at the text header of the snapmater file with a text editor. Find the recording unit, usually in volts (UNITS field). Then, find the voltage range in the "CHANNEL.RANGE" [cmin cmax] field. Finally, determine the gain of the amplifiers (directly on the machine, not in the header file). Knowing that the recording precision is 12 bits. The folowing formula 1/2^12*[cmax-cmin]*1e6/gain returns the relative gain. You have to compute it and enter it in the edit box. Enter 1, for preserving the data file units. (note that if the voltage range is not the same for all channels or if the CONVERSION.POLY field in the file header is not "0 + 1x" for all channels, you will have to load the data using snapread() and scale manually all channels, then import the Matlab array into EEGLAB). |
| Inputs: | |
filename |
SnapMaster file name |
gain |
relative gain. See graphic interface help. |
| Outputs: | |
dat |
EEGLAB data structure |
| Author: | Arnaud Delorme, CNL / Salk Institute, 13 March 2002 |
| See also: | eeglab(), snapread() |