Trigger Data from TCP/IP

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supat
Posts: 2
Joined: Tue Jul 31, 2018 1:38 pm

Trigger Data from TCP/IP

Post by supat » Tue Jul 31, 2018 1:55 pm

Hi, I am developing a MATLAB program that receives data from Actiview TCP/IP broadcast. I have successfully decoded TCP/IP packet and confirm that EEG data were decoded correctly.

However I got values I do not understand for the trigger data. For example, one of the decoded value from trigger channel is -1996490240.

The trigger was sent to BioSemi in form of binary-encoded decimal where each trigger channels represented 1 bit.

Also, according to my experiment design, interval between each trigger is 2 seconds, but by plotting signal from trigger channel, the value seems to change in 1 second interval.

I would like to ask what is the proper way to decode and interpret trigger signal received from Actiview TCP/IP?

Thanks,

Supat

Coen
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Re: Trigger Data from TCP/IP

Post by Coen » Wed Aug 01, 2018 8:35 pm

The trigger are bit 8-23 of the 32 bit integer, see https://www.biosemi.com/faq/trigger_signals.htm (ignore bit 0-7, bit 24-31 are status bits)

Best regards, Coen (BioSemi)

supat
Posts: 2
Joined: Tue Jul 31, 2018 1:38 pm

Re: Trigger Data from TCP/IP

Post by supat » Thu Aug 02, 2018 6:22 am

Thank you for your reply. It solved my problem.

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