Guralp Systems CMG-CD24 User Manual
Page 64
CMG-CD24
(These two commands have similar names; remember that a
component TRIGGERS the system, whilst taps and components can be
TRIGGERED.)
5.5.3 STA
Syntax: Z-secs N-secs E-secs STA
Sets the length of the “short-term” averaging period in the STA/LTA
triggering algorithm.
Z-secs, N-secs, and E-secs are the time period over which to
calculate the average for the Z, N, and E components respectively. If a
component is not considered by the triggering algorithm (see
TRIGGERS, above), the value you specify here will be ignored.
For example, 1 2 2 STA will calculate short-term averages for 1 s of
the Z component, and 2 s of the horizontal components.
5.5.4 LTA
Syntax: Z-secs N-secs E-secs LTA
Sets the length of the “long-term” averaging period in the STA/LTA
triggering algorithm.
Z-secs, N-secs, and E-secs are the time period over which to
calculate the average for the Z, N, and E components respectively. If a
component is not considered by the triggering algorithm (see
TRIGGERS, above), the value you specify here will be ignored.
For example, 15 20 20 STA will calculate long-term averages for 15 s
of the Z component, and 20 s of the horizontal components.
5.5.5 RATIOS
Syntax: Z-ratio N-ratio E-ratio RATIOS
Sets the ratio of STA to LTA above which a trigger will be declared in
the STA/LTA triggering algorithm.
Z-ratio, N-ratio, and E-ratio are the time period over which to
calculate the average for the Z, N, and E components respectively. If a
component is not considered by the triggering algorithm (see
TRIGGERS, above), the value you specify here will be ignored.
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