| OpendTect User Documentation version 3.2 |
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Name
Frequency Filter -- Attribute that returns filtered data using FFT or Butterworth filter types
Description
The specified Input Data is bandpass filtered with the commonly used Fast Fourier Transform or Butterworth filter. The difference between using the FFT or Butterworth filtering method is that, for the FFT, one considers the complete trace while for the Butterworth filter, only a "small" segment, depending on the selected number of poles, is taken into account. The user should keep in mind that using the Butterworth Filter results in a small shift in the seismic data.
The curves of the Butterworth filter for various numbers of poles
The Filter type is set to LowPass, HighPass or BandPass according as it is discriminating against frequencies above or below a certain limiting frequency or outside of a given band of frequencies.
User-interface for Fast Fourier Transform filter
User-interface for Butterworth filter