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STA/LTA
is a trigger algorithm usually used in the field of weak-motion seismology. The STA/LTA
continuously calculates the average values of the absolute amplitude of a seismic signal in two
consecutive moving-time windows. The short time window (STA) is sensitive to seismic events
while the long time window (LTA) provides information about the temporal amplitude of seismic
noise at the site. When the ratio of both exceeds a pre-defined value, the trigger is activated and an
event is recorded.
Figure 5.1.3. Trigger recording interface, in case of selection of STA/LTA as trigger mode.
5.1.3.
Timed recording
In the section timed recording you can set-up a timetable to record files automatically, in addition or
independently from the trigger. You set-up a
Starting time
, e.g. every Monday at 10 am (select
Weekly > Monday > once a week > 10 > 00
) or now (select
Hourly > Every hour >
minutes: 1
minute from now. The expert mode provides you with the features of CRON (as it is known on
LINUX systems) to set-up the start time.
At the
Starting time
, the SB starts recording according to the settings in the
Parameters
section.
Every
Period between recordings
starts with a recording of
Recording duration
. The rest of the
period, the SB is idle.
Number of recordings
tells the SB how often this procedure will be
repeated.
NOTE: Timed recording continues until you disable it or the unit is switched off.