System information

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Blastware Advanced Module
Blastware Operator Manual 6–31
The available filters:
• Low Pass Filter – This filter passes low frequencies but attenuates (reduces amplitude
and intensity of the signal) frequencies higher than the Cutoff Frequency – refer to
Bandwidth Pass Filter, below). This filter provides a smoother form of a signal which
removes the short-term oscillations, leaving only the long-term trend.
• High Pass Filter – This filter passes high frequencies but attenuates (reduces amplitude
and intensity of the signal) frequencies lower than the Cutoff Frequency – refer to
Bandwidth Pass Filter, below).
• Bandwidth Pass Filter – This filter is a combination of High Pass and Low Pass
Filtering; it is the Cutoff Frequency that rejects both low and high frequencies and keeps
all frequencies located in between.
The Cutoff Frequency is the reject value; The Low Pass Filter removes frequencies
above this value. The High Pass Filter removes frequencies below this value. The
Bandwidth Pass Filter removes frequencies indicated by both the Low and High Pass
Filters. The Bandwidth Pass Filter levels are entered in the lower text box, as indicated
in the figure above.
• Ponderation (France) – The Ponderation Filter is only used for compliance monitoring
to French National Standards. It is a frequency filter similar to the perception of the
human ear.
• Filter Weights from File – Performs filtering of Frequency weighting from a file
containing a weights table.
(1) Taper
The type of taper selected determines the overall characteristics of the filtering which takes
place. For Linear Taper, a fixed amount of attenuation per change in frequency occurs. For
Cosine Taper, a given percentage change in frequency does not produce a fixed amount of
attenuation. It is determined by the frequency.
f. Frequency Weight File
This function performs frequency weighting of an Event based on a frequency weights table file (a
.fwt file). To select an existing .fwt file, click on the Browse button and navigating through your
directories. You can also edit an existing file by clicking the Edit button, or create a new file by
clicking on New. The Edit dialog box appears: