Sending triggers from digital audio channel

Hardware Matlab Support
1

I am currently using MATLAB to send triggers via C-Pod to both EEG (Brain Vision actiCHamp Plus) and fNIRS (NIRx NIRS Sport 2) systems during an auditory experiment.

I implemented the MATLAB code provided to ‘write’ the triggers successfully, however, there is an inherent delay if I start the audio stimulus then send the trigger (or vice a versa). I have an even bigger issue with delays (in the hundreds of milliseconds) if I use frame-based audio to have continuous background noise while presenting target stimuli.

What I would like to do is send the trigger through one of the audio channels. The audio outputs to a Dante interface card (Focusrite RedNet PCIeNX) and therefore the digital signal arrives via ethernet cable.

Is there a Cedrus device that would transform the audio digital signal (via ethernet) to a TTL pulse?

2

StimTracker can easily handle marking of auditory events. It is also designed to handle multimodal experiments like yours, sending event markers to fNIRS and actiCHamp simultaneously and with zero millisecond difference.

There are also some advanced signal filtering options that were designed with audio in mind.

I hope this helps. Please let me know if you have any other questions. If you would like to chat by phone or Zoom, please send us an email.