Even though the claimed “ring oscillator” is “determined by the parameters of temperature,

voltage, and process,” it does not necessarily follow, as Plaintiffs’ argue, that the “ring oscillator”

must be non-controllable.53 The claims do not mention “controllable” or “non-controllable” in

relation to the “ring oscillator” and neither does the specification. The term “non-controllable” is

only used by the patent examinerin the prosecution history discussed above. Additionally, in the

preferred embodiment, the “ring oscillator” is “determined” by temperature, voltage, and process,54

which suggests at least one embodiment in which the ring oscillator is controlled.

Because of the clear limitation in the claims that temperature, voltage, and process determine

the “ring oscillator’s” frequency, the court includes those limitations in the construction of the term,

but does not find similar support for importing the “non-controllable” limitation. The court

therefore construes “ring oscillator” as “an oscillator having a multiple, odd number of inversions

arranged in a loop, wherein the oscillator is variable based on the temperature, voltage and process

parameters in the environment.”

AND

Plaintiffs also try to introduce evidence from the prosecution history to support their

argument. Although Plaintiffs quote a section from the prosecution history where the applicants

used the magic words “the present invention,” what the applicants disclosed is that the present

invention includes a variable speed clock on the same microprocessor as the CPU and thus its speed

will vary based upon environmental conditions.77 This is exactly what is claimed in claim 1. The excerpt goes on to explain that one advantage of the variable speed clock is that it “allows the

microprocessor to operate at its fastest safe operating speed,” but again, this is just one embodiment and not necessarily a requirement of the invention. Plaintiffs’ other citations to the

prosecution history are similarly unconvincing.