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User Guide
CEPAS
Figure 8. Low Pass Filtered. Elliptic Filter. Pass Frequency 200Hz, Stop Frequency 400Hz (filter order 4).
The wider filter produces less signal distortion and will remove all unwanted noise above 200Hz. Note that
there is not much high frequency noise in these signals anyway.
Some users have found a setting of 100Hz for the Pass Frequency and 400Hz for the Stop Frequency
minimises distortion. The wider transition band makes the roll-off less sharp. The less harsh the filter, the
less change occurs to the morphology of the signals.
The approach in CEPAS is to use only as much filtering as is useful. Some algorithms that are described in
detail in the next section of this guide have a filtering effect inherently built in and so specific time domain
filtering has limited usefulness.
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