Appeal No. 1998-2513
Application No. 08/171,427
separate loops. Rather than the capstan speed instruction based on tracking error being
input to adder 25 of prior art Figure 3, the examiner contends that the signal would be input
to speed error detector 21.
We agree with the examiner’s finding that the combined teachings of the APA and
Takeda would have suggested providing a capstan speed instruction, based on tracking
error, as input to speed error detector 21. The purpose would have been to increase
tracking accuracy of the prior art system as shown in appellant’s Figure 3 by using the
tracking error to help compensate for errors in speed. Takeda in particular at page 13,
first full paragraph of the English translation teaches using a processed signal, derived
from the tracking error signal, for determining the rotation speed of a capstan motor. We
do not find the teaching to be limited to the environment disclosed; that is, not limited to
circuitry in which a voltage signal from reference voltage generation circuit 7b is input to
“addition amplifier” 1. A reference is properly evaluated for reasonable inferences which
one skilled in the art would draw therefrom, and not just for its specific, express teachings.
In re Shepard, 319 F.2d 194, 197, 138 USPQ 148, 150 (CCPA 1963). Moreover, one of
ordinary skill in the art must be presumed to know something about the art apart from what
the reference discloses. In re Jacoby, 309 F.2d 513, 516, 135 USPQ 317, 319 (CCPA
1962).
In the context of the system of appellant’s prior art Figure 3, it is not clear that simply
adding another speed signal to summer 25 would be desirable, or would even result in an
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