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Synchronizing different types of stimulus events with Net Station

The EGI Geodesic EEG System (GES) has three different options for integrating stimulus presentation events into Net Station. In order of complexity, they are the Digital Inputs (DINs), the Experiment Control Interface (ECI) and the Amp Server Pro SDK (ASPSDK).

The DINs give the ability to add digital markers to the EEG record real time using a TTL style (5 Volt digital) signal connected to the net amps digital inputs. The benefit of using DINs is the simplicity of the solution, and that the events are communicated in real time and go directly to the amp. However, the downside of using DINs is that you only have the ability to add up to 255 unique markers, nor is there any control over Net Station or the amp.

The ECI is a more elegant solution and uses TCP/IP communication. This is what is achieved through the use of E-Prime and EENS (E-Prime Extensions for Net Station) together, and therefore allow for software control of things like the ability to start, stop and pause the recording mid-experiment and the ability to send over stimulus events to Net Station that have a rich data structure.  In this scenario, the events are not real time, but are instead sent over with a time stamp. Therefore, time synchronization must be handled. The ECI includes calls to synchronize external time-bases, either to a general clock or a Network Time Server. The former allows synchronization with a modest amount of programming and is currently supported by several third party packages. Synchronization using the Network Time Protocol (NTP) is currently only supported in E-Prime. 

Finally, the most complex option is the Amp Server Pro SDK. This is a software developer's kit and gives the user the same control over the amp as Net Station has. This option is typically not necessary for most projects and is mainly used by those that need real time access to the EEG data as it is streaming, such as those doing Brain-Computer Interface (BCI) projects. There is a cost associated to purchase this option and it also requires an expert level software programmer. 

Please contact EGI Support if you would like more information. 


Additional Info

  • Product Type: E-Prime, Net Station 5
  • Information Type: Implementation Theory
Last modified on Wednesday, 19 July 2017 14:11

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