Guralp Systems Scream - Manual (Page 44)

Scream! 4.5
4.3.2 Viewing spectra
You can overlay the power spectra of up to two streams on the
frequency graph. This is intended to help you design filters for
specific events by focussing on the frequencies at which the event has
significantly more energy than the background noise.
To design a filter for a specific event:
1. View the relevant stream in a Waveview window and click the
Pause icon ( ). Zoom in to a time period where the stream is
quiet.
2. Holding down the shift-key ( ), select a single stream across
this quiet time range. Choose Use in Filter Design… from the
drop-down menu. The Filter Design window will appear, with
the spectrum of the background noise overlaid.
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