The documentation for this block is no longer available, since this block is from a previous version of the DSP Blockset. There may be a newer version of this block, or a different block that replaces it. If so, you can get the documentation for that block.
To see if there is a newer version of this block, try the following:
simulink
at the MATLAB command line, and click on the DSP
Blockset entry. This gives you access to the most up-to-date versions of
the DSP Blockset blocks. Right-click on a block to get help.