Adding markers from stimulus presentation software

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.