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Example For Digital Filtering

WindDataSuite implements a module for filtering data with digital filters. In the following example, the raw data of the wind speeds in all heights (Fig.1) have been filtered with a low-pass filter (Fig.2) and with a band-pass filter (Fig.3).
The low-pass filter has a cut-off period (50% energy pass) of 4 hours and thus filters out all high-frequency signals (turbulence, gusts of wind) from the data (Fig.2).
The band-pass filter has a lower cut-off period of 18 hours and an upper cut-off period of 36 hours and thus yields in the main only the signal of the daily varibility yet (Fig.3).

Fig.1 Raw data
Fig.1:  Raw data of wind speed
Fig.2 Filtered data
Fig.2:  Digital filtered data of wind speed.
Low-pass filter, cut-off period 4 hours.
Fig.3 Filtered data
Fig.3:  Digital filtered data of wind speed.
Band-pass filter, lower cut-off period 18 hours, upper cut-off period 36 hours.
The filter response yields the signal of the daily variability around the mean.
 
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Data range : 1 year (365 days), sampling rate 10 minutes
Processed channels : 31 height levels of wind speed
Computing time : approx. 1 second
Processing time : approx. 1 minute