Reading in data from a new CTF system with ECC

Robert Oostenveld r.oostenveld at FCDONDERS.RU.NL
Wed Nov 29 18:14:05 CET 2006

Hi Michael

On 29 Nov 2006, at 15:11, Michael Wibral wrote:
> I'm trying to read in data from a CTF 275 channel system.
> ...
> When I use trialfun_ctf_continuous to read in the data no triggers are
> found and as a consequence no trials are defined - I wonder whether
> there is a problem with things like the 'STIM' channel and the
> [backpanel, frontpanel] stuff as the machine doesn't seem to have any
> back or frontpanel - but the ECC instead.

I indeed think that the problem is that trialfun_ctf_continuous
assumes back and frontpanel. The code in that trialfun predates the
read_event code, and it is not maintained. You can use
trialfun_general instead, or make your own trialfun. Read the help of
definetrial to see what trialfun_general can do for you (not too
much, but it might be enough).

Alternatively, have a look at the bottom of the page
to see a straightforward example trialfun. For that, you should also
look into read_fcdc_event.

We also use pseudocontinuous data at the Donders. Note that you have
to do cfg.datatype='continuous' in preprocessing and artifact detection.

> I have also tried to trial the data inside the CTF Software (using
> newDs
> with the corresponding markers) and then to use trialfun_ctf_epoched
> with the same result.

Also the trialfun_ctf_epoched is very old.

> BESA reads the triggers however without problems, both, their values
> (1,2,3...) and der names. so I think the data format shouldn't have
> changed too much.

No, the dataformat indeed did not change that much. It is also
already implemented in the read_fcdc_event code, and the general
trial function (or custom trial functions) can work with it.

best regards,

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