Appeal No. 1997-3156
Application No. 08/372,423
it is not necessarily true that in all integrated circuits a propagation delay increases
proportionally as temperature rises.
We need not reach the issue of whether temperature monitoring is suggested by
Swapp because we find that Swapp clearly does not teach or suggest the claimed control
for changing the operating frequency of the integrated circuit when a phase delay between
an output signal and a clock signal is longer than a predetermined value.
The examiner contends that this limitation is suggested by Swapp. More
particularly, the examiner urges that the skilled artisan would have recognized that
comparator 34 of Swapp is meant to detect slight differences in the phases of the clock
signal and the output of the device under test (DUT). The examiner concludes from this
that “if this difference became too great the comparator might not compare the correct
pulses, i.e., it might compare the clock pulse P with the DUT output pulse P " [answer-i i-1
page 4, emphasis ours].
In our view, the examiner’s position is based purely on speculation most likely
acquired from a hindsight knowledge of appellants’ invention. Swapp’s disclosure is of no
help in determining what would happen therein if the difference indicated by
comparator 34 became “too great.” It is not known at what level the comparator might not
compare the proper pulses, if at all. Thus, Swapp clearly does not indicate a
4
Page: Previous 1 2 3 4 5 6 Next
Last modified: November 3, 2007