Within the ARTeMIS Software it is possible to perform modal identification in the frequency domain in three different ways.
The Frequency Domain Decomposition (FDD) technique where each mode is estimated as a decomposition of the system's response spectral densities into several single-degrees-of-freedom (SDOF) systems.
The Enhanced Frequency Domain Decomposition (EFDD) emerges as an improvement of the first technique, where in this last case, the damping ratio estimation is available as an extra feature as well as enhanced eigenfrequencies and averaged mode shapes. In EFDD the modal parameters estimation is based on the FDD peak picking technique but extended with simple time domain least squares estimation technique.
Finally, the Curve-fit Frequency Domain Decomposition (CFDD) is somewhat similar to EFDD. However, the extension to the FDD relies on a frequency domain least squares estimation technique.
The techniques are based on manual peak picking on mainly the first singular value curve of the response spectral densities. However, an automatic peak picking option is also available for all three methods:
In general, the 2D and 3D Display Options are available for the frequency domain editors, as well as the 2D and 3D Display Properties. Properties specific for the frequency domain identification techniques are described in the Frequency Domain Decomposition Properties.