An extra zero sample after most resets¶
Most SNUADC resets (335 of 392) contain one sample that reads 0 in every channel at once, a little after the reset. It carries no time of its own: the signal either side runs on as if it were not there.
| Status | established: shown on many cases, with a control. |
| Devices | SNUADC |
| Variables | ECG lead II (SNUADC), Arterial pressure (SNUADC), Plethysmogram (SNUADC) |
What it means¶
A spike to the bottom of the range in every channel, and one sample more on the count than time passed. Detectors that see it as a value will misfire; timing by count is off by 2 ms after it.
What is done about it¶
Still stored as a value. Masking it is a pending decision.
Evidence¶
| Study | Date | Status | Summary |
|---|---|---|---|
| Records out of order at SNUADC resets, and where the lost time goes | 2026-10-17 | current | At every SNUADC reset the five records after it are written out of order: two continue the old timing and three start the new. Put back in order, the waveform runs on with no samples missing; the 18–20 ms lost at each reset goes missing inside the last old-timing record, and an extra zero sample follows. |