Select menu item <Analysis><Filter> to apply the Fast Fourier Transform (FFT) filters or the Daubechies D4 Wavelet Tranform for digitally filtering data.

FindGraph provides five filters for digitally filtering data: 

In dialog you can modify low and high frequencies and amplitude threshold level. 

An inverse FFT and Wavelet Transform is performed on the filtered frequency spectrum to yield a new data series containing the original data with the noise removed.