It seems our strongest position would come from a ruling that our patent is “unconcerned with the external clock implementation” in terms of it being an asynchronous clock or a synchronous derivation of the variable speed ring oscillator.
If it’s ruled that our patent only applies to implementations that use an asynchronous external clock then there may be room for design work-arounds which avoid infringing on this patent. The synchronous work-arounds I can think of might perform only marginally slower than if an asynchronous external clock were used – this may be preferred over paying for a license.
I hope we see a decision that rules the patent is valid and covers external clock implementations that are either synchronous or asynchronous.