[FieldTrip] Problem with unwanted 'normalisation' of data using ft_realtime_signalviewer

[Christian Walsh]

Dear community,

My name is Christian Walsh and I am doing a Neural Engineering MSc. in TCD
in Ireland. My thesis is on the effects of timed auditory stimulation on
sleep quality. A sort of dumbed down and scaled down version of a recent
enough study by Ngo et al. (2013) entitled: Auditory Closed-Loop
Stimulation of the Sleep Slow Oscillations Enhances Memory.

For this, I detect peaks and troughs in the ongoing EEG data in realtime.
On detecting a trough, a sound is played back after an initial delay. This
is done so that the sound playback coincides with the peak of the ongoing
EEG data. Before I can actually perform this experiment I need to setup the
apparatus.

To do this I have simulated realtime streaming and analysis using the
ft_realtime_signalproxy function in one MATLAB session and an
edited_ft_realtime_powerestimate and psychtoolbox function in another
session. This is all working fine. The problem is that the data that is
streamed in is normalised, scaled or something. i.e. the y-values of the
streamed data should range from around -150 uV to 150uV but the
edited_ft_realtime_powerestimate function only displays y-values between
around -2 and 2???

I'm new to programming so apologies if this is a stupid question. I have
looked into editing some of the ft_read_data and ft_preproc_baselinecorrect
functions but have not found a solution.

Advice would be appreciated,

Cheers,

Christian
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