cannot convert gradiometer definition back to axial, please contact Robert

Robert Oostenveld r.oostenveld at FCDONDERS.RU.NL
Mon Jun 11 14:57:53 CEST 2007

Hi Sameer,

On 7 Jun 2007, at 22:11, Sameer Walawalkar wrote:

> Hello Robert,
> I have been playing around with
> fieldtrip/doku.php?
> id=fieldtrip:documentation:tutorial:statistics#3_permutation_tests_for
> _time-frequency_representations
> in an attempt implement non-paramteric statistical testing of
> coherence diferences between trials. My screen currently reads:
> the input is freq data with 612 channels, 18 frequencybins and 11
> timebins

How did you manage to get 612 channels? Are you computing planar
channels from your planar channels? Your neuromag system already has
planar channels (by hardware design), hence you should not call
megplanar on your data. The megplanar function is meant for computing
planar gradients from a hardware magnetometer system (or a hardware
axial gradiometer system, such as our CTF).

After preprocessing and timelockanalysis or freqanalysis you should
do combineplanar.

> Warning: trying to convert planar to axial gradiometers, this is
> experimental
>> In combineplanar at 280
>   In Auto_nonparametric_coh at 47
> ??? Error using ==> combineplanar at 308
> cannot convert gradiometer definition back to axial, please contact
> Robert
> Error in ==> Auto_nonparametric_coh at 47
> TFR_LL_000_500_planar_cmb = combineplanar(cfg, TFR_LL_000_500_planar);
> So, I am getting in touch with Robert Oostenveld.

best regards,

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