• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 47 subscribers
  • Views 459 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS1299-4: ADS1299-4 : ADS1299-4: Signal Quality Measurement and Register Configurations

user6167334
Prodigy 30 points
Part Number: ADS1299-4
Other Parts Discussed in Thread: ADS1299

We built a 4-Channel EEG measurement system that is based on ADS1299. We have been experimenting on different Register  Configurations settings  and we obtained some results. We are quite sure how good or bad the signal quality is.

We have two questions. One Informative  and the other  is a technical question.

Question 1 (Informative): Can someone recommend us a company or freelancer in Germany  (or around) who is an expert in ADS1299 and can offer professional EEG Signal QUALITY consultancy. (Sorry if this is not the right place to ask such questions).

Question (Technical) :

After we received the 24 bit hexadecimal output of ADS1299, we converted it into decimal numbers using this formula from the document :

voltage = code * Vref / [PGA gain * (2^23-1)

The configure our gain to be 24. We used Vref =4.5.  The question is when can we use Vref=2.5?

Secondly, below is  part of the raw EEG signal we obtained using the above formula.  Is this EEG signal or just some noisy artifacts?

Lastly, how can we compute Alpha, Beta, Theta, Delta waves from this signal? We should note that we are not using the Open BCI board.

Signal from some electrodes (First 20 sample point):

Sampling Frequency: 250 Hz

 Electrode1:

0.115835568706461,-0.0646460282380615,-0.0448426955750818,0.0516473488983332,-0.0638967307086862,-0.0584033648256498,-0.0778067353733463,-0.186205901051271,-0.156537871842131,0.120433277837429,-0.0892165856619579,-0.0571902015435936,0.0648374485775767,-0.0766924338570158,-0.100786765013548,-0.0199855440837793,0.0908620540335243,0.0689515777172539,0.0248223945286744,0.173917224874166 ....

Electrode 2:

0.0762122736826269,-0.0335254709154929,0.167718862619264,-0.061558537072961,0.13287088368784,-0.0769389512466134,0.151050585633586,0.0839137684004031,-0.130509198368692,-0.17473489638983,0.0846802544212645,-0.185863517029705,-0.118497907340277,0.1316463657196,-0.0414169331093947,0.0706212083245764,0.111499799668765,0.033622678652129,0.0495750516146483,0.061116419567635

  • 0
    Prodigy 30 points

    We are quite sure how good or bad the signal quality is.  == We are NOT quite sure how good or bad the signal quality is.

  • 0 in reply to user6167334
    TI__Guru 66406 points

    Hello,

    Welcome to our forum and thank you for your post!

    Unfortunately, we do not have a recommendation for EEG consultation.

    Regarding your other questions:

    1. The ADS1299 only supports a 4.5-V internal reference voltage. If you wish to use a smaller reference, you would need to apply it externally. 
    2. We are not the experts in EEG signal analysis, so we cannot comment on how to distinguish EEG signals and their sub-components (alpha, beta, delta waves, etc.). For this I recommend finding a consultant who can work with you on filtering algorithms to identify these components.

    Best regards,

  • 0 in reply to Ryan Andrews
    Prodigy 30 points

    Dear  Ryan,

    Thanks for your reply.  In my question, I presented the outputted raw EEG signal results of two Electrodes in Volt.

    Are these real EEG signal or some noise artifacts?

    Thanks & Best Regards.

  • 0 in reply to user6167334
    TI__Guru 66406 points

    Hello - as I said in my previous reply, we do not have the medical expertise to identify those signals as EEG or noise.

    Best regards,