My lab has been performing 24/7 recordings with up to 96 channels for over a year now. We've noticed two issues recently in 10% of our recordings, where it occurred more often as we upgraded from v0.4 to v0.5.4:
1) Byte difference: Some channels have more blocks than the others. We are noticing exactly byte differences in multiples of 2070, consistent with how OEP records blocks. By the end of a 24hr recording, we've seen differences of up to 5 blocks between CH1 and 64 (Fig 1).
2) Timestamp difference: This is related to #1, where we see timestamps diverge from CH1 and CH64 by a constant amount (Fig 2)
3) Data Loss: Upon investigating #1 and #2, we noticed significant data loss, up to 12 minutes in a 22hr recording. We did not see any error from the machine, or have any logs that indicated this. However, we saved a screenshot of the GUI after we stopped the recording, indicating we recorded for 1341min 49s, or 80509s (Fig 3a). The amount of datapoints outputted only reflected 79767s of data.
We looked at the timestamp variable and noticed it jumped within the first 15min of recording, indicating acquisition problems of up to 10s before resuming (Fig 3b).
We looked at the cross correlation across our 64 channels towards the end of our recording and noticed significant time lag (Fig 3c). To us, this indicates we would need to adjust each channel to its own timestamp.
Our questions are:
1) Have these de-sync issues across channels been seen before?
2) Are there supposed to be error messages associated with this data loss?