Tool/software:
We are seeing what appears to be a ~10.4 Hz spur plus harmonics on all output channels of a full ADS1299. More precisely, it looks like an artifact with a 24-sample period based on the 250-Hz sampling rate, because using the ADS1299 as the time reference, with part-to-part variations on internal oscillator accuracy, real 60-Hz noise picked up on the sensor cables appears at slightly different frequencies in the FFT, whereas the artifacts are always at the same frequency. The artifact level is not high enough to discern from the time plots but can be seen in the FFT and is well above the noise floor. No artifacts are seen with the internal ADS1299 test signal, or if a channel input is shorted to the reference. What could be causing this phenomenon?
