Appeal No. 1997-1183
Application No. 08/066,362
In reaching our decision in this appeal, we have given careful consideration to the
appellants’ specification and claims, to the applied prior art references, and to the
respective positions articulated by the appellants and the Examiner. As a consequence of
our review, we make the determinations which follow.
CLAIMS 1-4
With respect to the combination of Kameyama with (Singh or Micheel), appellants
argue the references individually, asserting that “none of the references discloses the
entire claimed invention.” (See brief at page 7.) These arguments are not persuasive
since the rejection is based upon the combined teachings of the references. Appellants
further traverse the Examiner’s conclusion that it would have been obvious to one of
ordinary skill in the art at the time of the invention to implement a negative differential
resistance device in the parallel signed digit adder of Kameyama. We disagree with
appellants. Appellants further argue that “[s]uch results [redundant encoded
representations where ripple carries are never produced] are not obtained without the
combination of the negative differential resistance devices and the sign redundant digit 4,3
coded [words], as required by the claims-in-issue. Such results are clearly unexpected.”
(See brief at pages 7-8.) We disagree with appellants. Clearly Kameyama teaches the
skilled artisan that signed-digit adding reduces the carry propagation problem and
increases speed of the manipulation. (See Kameyama at col. 1.) Kameyama discloses
that the “carry propagation is always limited to one position to
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