Flatness of frequency response - 10-100hz
Hi everyone, did anybody do a frequency sweep analysis (or any other kind of input frequency response) test on the chip?
In my case with my own designs with the ADS1299 I get the influences of a low pass that is not specifically designed or introduced anywhere - cutting off the signal starting from ~10Hz on with a 3dB cutoff at 50Hz.
This means that from 1-100 Hz the frequency response is neither completely flat, nor linear!?
EEG Example: In Alpha (8-13 Hz) the attenuation already differs around about 8%. (8hz: 0% - 13Hz: 8%). This can not be a characteristic of the ADS1299, can it?
Best
Alex
In my case with my own designs with the ADS1299 I get the influences of a low pass that is not specifically designed or introduced anywhere - cutting off the signal starting from ~10Hz on with a 3dB cutoff at 50Hz.
This means that from 1-100 Hz the frequency response is neither completely flat, nor linear!?
EEG Example: In Alpha (8-13 Hz) the attenuation already differs around about 8%. (8hz: 0% - 13Hz: 8%). This can not be a characteristic of the ADS1299, can it?
Best
Alex
Comments
I did not see the posts before, however they do not really satisfy me - as I am looking for the attenuation over frequency (and not noise over frequency) - so a typical bode diagram or similar of the frequency response, that's what I hope to find.
I posted the issue also in the Texas Instruments E2E forum and some guy of their staff is caring about it right now. Still - if any of you guys did some measurements or knows something about the issue - please share!!
Best
Alex
http://e2e.ti.com/support/data_converters/precision_data_converters/f/73/t/475854
William