what is going on with the raw trigger data?

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dmedine
Posts: 7
Joined: Sat Jan 16, 2016 12:22 am

what is going on with the raw trigger data?

Post by dmedine »

Why does the raw trigger data look like this:
raw_trigger_data.png
raw_trigger_data.png (8.04 KiB) Viewed 4225 times
Close up showing expected shape of trigger with unexpected trigger values (and one of the intermittent huge negative spikes):
closeup.png
closeup.png (13.7 KiB) Viewed 4225 times
I would expect an integer value corresponding to the actual active pins on the parallel port connection. So two questions, what is the meaning of the huge negative floating point numbers and why the huge negative spikes every 5 seconds or so?

Coen
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Re: what is going on with the raw trigger data?

Post by Coen »

The samples are 24-bit words. The 16 least significant bits are the 16 trigger lines. The 8 most significant bits are used for system status, see https://www.biosemi.com/faq/trigger_signals.htm .

Best regards, Coen (BioSemi)

dmedine
Posts: 7
Joined: Sat Jan 16, 2016 12:22 am

Re: what is going on with the raw trigger data?

Post by dmedine »

That makes sense. Thanks for pointing me to the FAQ. Somehow I couldn't find the documentation for this.

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