Filter

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: 

• The low pass filter allows you to eliminate noise at high frequencies.
• The high pass filter to eliminate noise at low frequencies.
• The band pass filter allows you to eliminate noise above and below a specified frequency range.
• The band block filter allows you to eliminate noise within a specified frequency range.
• The threshold filter allows you to eliminate noise corresponding to frequency components that are below a specified threshold.

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.