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Serial marker timing

This page provides and explains the timing test we did to validate the timing of the serial markers one can send to the VU-AMS device.

We used an OpenSesame experiment to send out a signal via the LPT printer port (which we know exits the PC virtually instantaneous) and a serial marker to the VU-AMS device using an AMSi USB cable. Now we fed the LPT signal to the VU-AMS PCG input which is sampled at 1000Hz. The images below show the serial marker appears in the VU-AMS data 1 or 2 milliseconds after the PCG signal changes (meaning the LPT printer port goes high). This means the serial markers can be used to accurately mark important moments in the VU-AMS data.