The Fosgate Model 3 was a great Servo-Logic surround processor. Since then, Jim Fosgate went on to design 6-Axis processing and after that he went on to design DPL II. DPL II was designed by Jim Fosgate. As far as I know, DPL II is only implemented digitally.

As I understand it, Jim Fosgate was chosen to design DPL II because the folks at Dolby liked what they heard with Fosgate's 6-Axis.