Filter

Command:

Math -> Filter...

Linear time-invariant filters are a general class of filters which can be calculated by a simple equation. After clicking the command Math/Filter... a dialog is displayed which can be used to set up the filter parameters. The general approach in applying a filter is to select the column (or row) which contains the raw data and write the filtered data back to another column (or row).

The filter dialog offers the following settings:

Setting	Description
Filter Type	General FIR Filter (FIR) General IIR Filter (IIR) Moving Average (MA) Weighted Average (WA) 2nd Order Savitzky-Golay Polynomial (POL) Smoothed 1st Derivative (1DV)
No. of Coeff. N	The number of filter coefficients may vary between 1 and 100. For polynomials and the smoothed 1st derivative the number of coefficients must be odd and may vary between 5 and 25.
Load/Save Filter Coefficients	Filter Coefficients which have been entered manually may be saved and loaded to and from the disk.
Apply to Columns/Rows	The user can choose to apply the filter function either to columns or to rows.

In order to apply a filter function to data, you have to click the button Apply Filter. After selecting the source and the destination column (or row) the filter function is applied to the source data and the resulting filtered signal is written into the destination column (row).