Sampling rate or time delay

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Sampling rate or time delay

Post by leila » Thu Oct 13, 2016 3:44 pm

Hi. I would like to ask a question about Actiview Software. When I open and read the bdf files for my subjects, I see less events (half) than the ones sending from my script. The events in each trial are different based on the frequency I send (8, 20, 33). When I calculate the frequencies from bdf files are also half. Could it be that I have chosen wrong sampling rate (I chose 2048 Hz) or could it be a delay in the timing? Why half of the events are read?
Thank you

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Re: Sampling rate or time delay

Post by Coen » Thu Oct 13, 2016 5:34 pm

ActiView records all triggers sent to the trigger port on the USB-receiver, regardless of sample rate, provided that the trigger duration is longer than the sample period (as selected with the speedmode switch).

If triggers are missing, then they are to short (less then 0.5 ms in case of 2048 Hz), or they are not sent.

Best regards, Coen

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