I believe, in this claim the defendants are attempting to limit their exposure(infringement) by simply saying the oscillator control signal must come from the "same semicondutor substrate".                        The plaintiff was possibly seeking a "broader" set of circumstances to included semi condutor substrates with external clocks/controls and possibly more infringement??                                                   Also the defendants state the plaintiff "disclaimed" use of external signals in order to distinguish over prior art.(Plaintiff had to be concerned about prior art)  Thus this limited the issue to "oscillator signals coming only from "same semiconductor substrates" SOC's -Systems on a chip.

From the ruling:

” The dispute is whether the ring oscillator may rely on a control signal or an external crystal/clock generator. In support of their construction, the defendants argue that the applicant disclaimed use of a control signal and a external crystal/clock generator in order to distinguish over prior art. The plaintiffs contend that it did not disclaim all types of control signals, such as voltage and current controlled oscillators; there was only a disclaimer of the more narrow “command input.” In addition, the plaintiffs argue that, although an external crystal is not directly used to generate a system clock signal, the external crystal can be used as a reference signal to account for delay across certain circuit  elements. The Court agrees with the defendants that the applicant disclaimed the use of an input control signal and an external crystal/clock generator to generate a clock signal. See Response to Office

Action, April 11, 1996, at 8; Response to Office Action, January 13, 1997, at 4; Response to Office Action, July 7, 1997, at 3-4. Accordingly, the Court construes the term to mean “a ring oscillator variable speed system clock that is located entirely on the same semiconductor substrate as the CPU and does not directly rely on a command input control signal or an external crystal/clock generator to generate a clock  signal.”