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18: Short Epoch Filtering
The following are brief descriptions of the numbered items from Figure 18-1.
1. Filter Settings pane. Controls the type and specified frequency of the filter. You can
select one or both of the two filter types—lowpass and/or notch—and the width of
the notch filter. A graphic display above the controls shows the contour of the chosen
filter band.
The controls in the pane include:
• Lowpass: Select the checkbox to activate the slider and the text box. Drag the
slider to the desired frequency, or directly input the frequency into the text box.
• Notch: Select either 50 or 60 Hz for the notch filter. Typically, line noise is 60 Hz
in the United States, and 50 Hz in most other countries; Japan uses either
frequency, depending on the region.
• Filter indicator: displays the type of filter chosen.
• Auto Set Filtering Specification Name: when this checkbox is selected, the
specification name is automatically set to match the current filter setting. For
example, Figure 18-1 shows a 100 Hz lowpass filter, so the name is 100Hz
Lowpass.
2. Preview Filtering pane (with file selector). Displays the effect the filter will have on
a selected file. Two windows display the Unfiltered and Filtered versions of the file.
You can select the file using the file selector in the lower-left corner of the pane. For
more information about the file selector, see “The File Selector and Associated Display
Panes” on page 46.
• Cycle Channels checkbox: Select this to automatically display one channel after
another in numerical sequence, in the Unfiltered and Filtered windows.
168 Net Station Waveform Tools Technical Manual S-MAN-200-WFTR-001 • December 21, 2006