Guralp Systems CMG-3ESPCD - Manual (Page 48)

CMG-3ESPCD Digital Broadband Seismometer Using Scream!
LTA periods, together with the Ratio, without restarting the digitiser (see
section 5.2 on page 53).
Since it is not generally advisable to trigger from broadband data, the digitiser
provides a set of standard bandpass filters to apply to the data streams before
they are tested for the trigger condition. This filtering serves to maximise
sensitivity within the frequency band of interest, and filter out noise outside
this band. You can select which bandpass filter to use from the Bandpass
filter drop-down menu. The corner frequencies of the pass band of the filter
are determined by the Nyquist frequency, which is given by the sampling rate
of the triggering data. The three filter options have pass bands between 10%
and 90%, between 20% and 90% and between 50% and 90% of the data’s
Nyquist frequency, respectively.
The possible filter configurations are shown in the following table:
Tap # Rate
(samples/s)
Bandwidth 1
(Hz)
Bandwidth 2
(Hz)
Bandwidth 5
(Hz)
0 200 10 – 90 20 – 90 50 – 90
1 100 5 – 45 10 – 45 25 – 45
50 2.5 – 22.5 5 – 22.5 12.5 – 22.5
40 2 – 18 4 – 18 10 – 18
25 1.25 – 11.25 2.5 – 11.25 6.25 – 11.25
20 1 – 9 2–9 5–9
2 50 2.5 – 22.5 5 – 22.5 12.5 – 22.5
25 1.25 – 11.25 2.5 – 11.25 6.25 – 11.25
20 1 – 9 2–9 5–9
10 0.5 – 4.5 1 – 4.5 2.5 – 4.5
8 0.4 – 3.6 0.8 – 3.6 2 – 3.6
5 0.25 – 2.25 0.5 – 2.25 1.25 – 2.25
4 0.2 – 1.8 0.4 – 1.8 1 – 1.8
2 0.1 – 0.9 0.2 – 0.9 0.5 – 0.9
3 25 1.25 – 11.25 12.5 – 11.25 6.25 – 11.25
10 0.5 – 4.5 1 – 4.5 2.5 – 4.5
5 0.25 – 2.25 0.5 – 2.25 1.25 – 2.25
4 0.2 – 1.8 0.4 – 1.8 1 – 1.8
2 0.1 – 0.9 0.2 – 0.9 0.5 – 0.9
1 0.05 – 0.45 0.1 – 0.45 0.25 – 0.45
MAN-C3E-0002 48 Issue B - November 2013