Recording pauses of about 20 s¶

In 29% of files every device jumps forward together, by a median 19.6 s: the recorder paused. Data are missing there, and the stamps show it honestly. The pauses run on a 5-hour timer: consecutive pauses in a recording are 5 h apart (plus the pause) in 86% of cases, and the first comes at any time after the recording starts.

What it means¶

Gaps common to every device are recorder pauses, not clock steps; nothing needs correcting. A recording longer than 5 h that has had one pause will have another 5 h later.

Detail¶

From the steps between records (19 October): 1,713 pauses of 15–25 s in the SNUADC with a BIS gap within 3 s, in 1,605 recordings. Of the 108 intervals between two pauses in one recording, 93 (86%) lie between 17,990 and 18,050 s, and only 3 are longer. The first pause comes a median 1.5 h after the SNUADC starts (10th–90th percentile 0.4–3.8 h), so the timer does not start with the recording, like the BIS and Primus correction timers (When each device's clock is corrected, in every recording). This is the 5-hour limit on SNUADC segments (Gaps and unbroken segments in every waveform): a segment can only reach 5 h when it starts at a pause. The cause (a 5-hour job on the recording PC, or in VitalRecorder) is not known.

Evidence¶