System information

Blastware Advanced Module
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6–28 Blastware Operator Manual
b. Central difference (5 points)
This option differentiates a waveform to determine the velocity along the entire waveform. The
five point central difference method uses a fourth degree polynomial to fit the waveform over five
points then calculates the slope. This method proves less sensitive to high frequency noise and
produces a smoother waveform. Click in the checkbox to display a checkmark to enable this
option.
Note: Blastware automatically enters the units for the result channel. A maximum of six
characters can appear. Process waveforms with units exceeding this number display an
asterisk (*).
6.9.9 Filter
WARNING: It is important to remember that applying Windows and Filters distorts the original
waveform.
The Filter command presents a series of functions to condition waveforms, including Filters and
Windows. The Low Pass, High Pass, and Bandwidth Pass Filters perform filtering on
waveform data in the frequency domain. The Low Pass Filter removes frequencies above the
corner frequency, while the High Pass Filter removes frequencies below the corner frequency.
To access the Filter command, an event must be opened using the Analysis tool. Use the analysis
cursors to analyze any part of a selected waveform. The cursors indicate Event time and
amplitude. After opening and Analysis window, display the filter dialog box opening the Process
Menu and selecting Filter.
Bandwidth Pass
Name Result
Analysis Cursors Analysis Window