The following new structures are supported in "realizeNTF()" and "realizeQNTF()" of newest Delta Sigma Toolbox(Version 7.3, July 3, 2009) of MATLAB which was developed by Richard Schreier.

  (1) PFB ; Parallel feedback
  (2) PFF ; Parallel feedforward
  (3) Stratos ; A CIFF-like structure with non-delaying resonator feedbacks, contributed in 2007 by Jeff Gealow

Is there anyone who know these structure ?

For example, what is the difference between "PFF(Parallel feedforward)" and the "FF(Feedforward)" ?