Description: You can now reduce high-frequency noise in X–Y data objects more effectively by using new and enhanced functions that reduce this noise without introducing a phase shift or aliasing in the output data. The classical Butterworth filter and Chebyshev Type I and II filters, new to Version 6.6, reduce this noise by attenuating at least half the signal noise above a user-selected cut-off frequency. The Chebyshev filters also allow you to control the filter's ripple factor, which determines how much oscillation you will allow in return for an improved filter response.

SAE filtering, available in earlier releases, has been expanded to allow you to perform general SAE filtering or to filter based on one of five SAE classes. The general SAE filtering does not use a specific SAE class, but enables you to filter based on a user-specified cut-off frequency. ABAQUS/CAE uses a separate, class-specific operator for each supported SAE filtering class, and this release introduces support for the 1000 class of SAE filtering.

The sine-Butterworth filter, available in previous releases, now enables you to specify a data sampling rate before the filtering occurs. This change improves the filter and reduces the chances of an aliasing of the data.

In addition, you can decimate an X–Y data object without filtering any high-frequency noise from the data. Because this option reduces the size of a large X–Y data object without introducing aliasing in the output, it can be an effective first step to perform before you operate on the X–Y data object in other ways.

Finally, Version 6.6 allows you to interpolate the data from X–Y data objects with nonuniform sampling rates. This operator enables you to set the sampling rate by specifying the size of the increment on the X-axis between values in the data object.

Visualization module:
   ToolsXY DataCreate: Operate on XY Data:
      butterworthFilter(X,I)
      chebyshev1Filter(X,I),
      chebyshev2Filter(X,I),
      decimateFilter(X,I),
      interpolate(X),
      saeGeneralFilter(X,F),
      sae60Filter(X,F),
      sae100Filter(X,F),
      sae180Filter(X,F),
      sae600Filter(X,F),
      sae1000Filter(X,F), or
     sineButterworthFilter(X,F)