Appeal No. 1997-1185
Application No. 08/497,845
lines 7 and 8 (all independent claims of this application).
This difference is used to calculate the additional time delay
added to the clock net. Hooper and Hitchcock adjust time
delays by changing circuit components, without changes to the
clock net. Note Hitchcock, where it states:
From Fig.2, one can observe a funneling of
negative slack values through block BA. If BA could
be replaced by a circuit having a smaller delay, all
the negative slacks could be eliminated without
changing functional design at all. (Page 102, right
column, second full paragraph.) (Emphasis added.)
Similarly, Hooper states in the abstract:
The timing debt can be used as a criterion
to determine when the implementation of circuit
component should be changed. (Emphasis added.)
Although the Examiner has noted instances of using
delay in the clock net (e.g., Hooper, column 5,lines 31-47),
the claimed calculation recited supra, using the worst delay
time margin and the secondary worst delay time margin, is not
disclosed or suggested by the references.
The Federal Circuit states that "[t]he mere fact
that the prior art may be modified in the manner suggested by
the Examiner does not make the modification obvious unless the
prior art suggested the desirability of the modification."
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