[FieldTrip] ft_artifact_threshold and the return of the "unit circle" error

[Tristan Davenport]

I'm trying to import and analyze some Neuromag 306 data, and I keep running
into the following error message whenever I try to detect blink artifacts
with the threshold method:















*??? Error using ==> filter_with_correction at 44 Calculated filter
coefficients have poles on or outside the unit circle and will not be
stable. Try a higher cutoff frequency or a different type/order of
filter.Error in ==> filter_with_correction at 44   error('Calculated filter
coefficients have poles on or outside the unit circle and will not be
stable. Try a higher cutoff frequency or a different type/order of
filter.');Error in ==> ft_preproc_bandpassfilter at 148   filt =
filter_with_correction(B,A,dat,dir);Error in ==> preproc at 299if
strcmp(cfg.bpfilter, 'yes'),     dat = ft_preproc_bandpassfilter(dat,
fsample, cfg.bpfreq, cfg.bpfiltord, cfg.bpfilttype, cfg.bpfiltdir,
cfg.bpinstabilityfix); endError in ==> ft_artifact_threshold at 148  dat =
preproc(dat, channel, offset2time(cfg.trl(trlop,3), hdr.Fs, size(dat,2)),
artfctdef); *
Based on previous advice in these threads, I have tried changing the cutoff
frequency, order, direction, and type of filtering of my data using cfg
fields like bpfreq, bpfilttype, bpfiltdir, and bpinstabilityfix. Long story
short, I've tried every logically possible combination of filter settings
(including no filtering at all), and I get the same error regardless. Does
anyone have some insight into this?

Take care,
Tristan Davenport
UC San Diego
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