After a quick look, I found this.

< If all of the claim's elements are found in the technology, the claim is said to "read on" the technology; if a single element from the claim is missing from the technology, the claim does not literally read on the technology and the technology does not infringe the patent with respect to that claim.>

So, it would appear that we need to define variable speed clock to make the determination of whether Barco is infringing on the 336. If no variable speed clock, then not infringing.

Corrections welcomed.

Opty