Part Number: ADS1299
Hello,
We are currently performing tests on our prototype device containing a 7-channel EEG system with the ADS1299. On the bench level, we are seeking to analyze the effects of impedance mismatches between channels. For our particular test case, the signal generator we use outputs the same signal across all channels. Therefore, we have our INxNs connected to the signal generator output and SRB2 (our reference electrode) to GND to avoid common-mode input. To simulate bad contact for an electrode, we added a series resistor between the signal generator output and the reference electrode. We found that the greater this resistance value, the worse our interference became.
For example, the image above is with a 300k series resistor while the other electrodes are shorted to the signal generator output, causing low-frequency interference that significantly degrades signal quality. Under balanced conditions, the only visible peak is that of the input frequency. Is there a way to mitigate this effect?
Let me know if you need any further information, thank you.
