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2.4  Identification options

Several options need to be defined in order to well specify the frequency domain on which data must be identified, the type of mesured data, the model used to fit, informations on colocated measurents and how to use them.

Identification options accessible from the Ident tab or from the command line through the pointer ci.IDopt (see idopt for the full documentation).

Description of the buttons line by line :

• Idopt The working frequency band selection specify on which frequencies must the data be identified.
  • w0 : Resets the working frequency band to the min-max boudaries. This button is similar to clicking on the button and double clicking on the measurements in the iiplot window.
  • wmo : Allows to specify min and max frequency by clicking two times at the minimum and then the maximum frequency locations on the measurements in the iiplot window. This button is similar to clicking on the button .
  • bandwidth history : Each modification of the working frequency band is stored in this history list and allows to quickly going back to previous selections.
• Fit : Several pole/residue models can be used to extract shapes from a list of identified poles, whose complete description can be found in section section 5.6
  • residue type : Specify which type of pole/residue model to use : complex mode residues with symmetric pole structure, complex mode residues with asymmetric pole structure or normal mode residues with symmetric pole structure.
  • residual terms : To takes into account the influence of out of band modes, residual terms should be used.
• data : Specify if the measured transfers are of type displacement/force, velocity/force or acceleration/force
• I/O : Information on colocated measurements are needed to enforce the constraint of reciprocity (see section 2.9.2) using the id_rm algorithm
  • nsna : Display to check if the number of sensors and actuators is correct (if it is not correct, the .dof table defining inputs and outputs of each transfers should be verified, see curve Response data)
  • Recip : Specify how the colocated informations should be used (see section 2.9.2 and idopt for more details)