Real time process of EEG signal

[nlaurenzano]

Hi all! I'm new in the LabVIEW world.

I recently joined a research group and we are considering working with LabVIEW. But before we make our final decision on buying LabVIEW and the necessary hardware components, we would like to know if it fits our project.

We intend to processing an analog EEG signal (available via BNC cable) in real time, in order to detect specific events. So our major concern is whether LabVIEW is able to perform the following operations fast enough:

1. Signal filtering between 11 and 17Hz.
2. Calculation of the envelope, i.e. the hilbert transformation or root mean square, over 100 or 200 ms windows
3. Sending a TTL trigger based on a threshold criteria.


The corresponding hardware we have in mind are the NI PCIe-6320 board with a BNC-2020 connector block. And we would be using LabVIEW 2012 Professional on Windows 7.

[Bob_Schor]

You don't mention the sampling rate (I presume 1KHz is sufficient), but LabVIEW 2012 should have no difficulty with this.  Are you aware of the LabVIEW Biomedical Toolkit, which I believe has EEG algorithms included?

[nlaurenzano]

Right, I forgot the sampling rate. We will be working around 200Hz, so that should be no problem then.

I think we won't need the Biomedical toolkit, but we will definitely check it out.

Thanks for your answer!

[Norbert_B]

The major challenge on your stated information is that you are going to work with Windows.

Windows is not a deterministic OS. That means that you can have any kind of timing jitter at any time. The common jitter does not exceed 1-10ms in average, but you can have spikes of up to even several seconds at any time (e.g. if virus scanner scans or hard drive is indexed, ...)!

So regarding the hard limits of your timing requirements, you might want to switch to a deterministic system, either Real Time (RT) or even FPGA (which seems to overblow the requirements....).

Norbert

[nlaurenzano]

Thank you, Norbert.

I expected Windows might be a problem. We are going to check the necessity of a real time system in the early stages of testing our project.

[srm@viewpointusa.com]

the issue will be the trigger signal delay and jitter under windows.  if you are trying for real time, you must determine what your real time requirements are.  how much jitter and delay can your application stand?