Appeal No. 95-3917
Application 07/861,144
Kalaf
Figure 1 of Kalaf discloses an autonomous gain normalization circuit. "The output of the input
circuit 10 is provided to a transimpedance amplifier 12 which comprises a reset switch 20, a fixed capacitor
22 and a plurality of switchable capacitors 24-30 connectable in parallel with the fixed capacitor 22 via
switches 32-38, which preferably comprise transistors" (column 3, lines 39-44). "[C]onnecting the
switchable capacitors 24-30 in parallel with the fixed capacitor 22 reduces the gain of the transimpedance
amplifier 12 by an amount proportional to the ratio of the switched capacitor 24-30 to the fixed capacitor
22" (column 3, lines 59-63). "The feedback circuit 44 [unnumbered in figure 1] is operative to effect
connection of selected capacitors 24-30 in parallel with the fixed capacitor in direct response to the value
of the digital output word" (column 4, lines 26-29). Thus, Kalaf has a network of a plurality of
interconnected passive elements (capacitors 24-30) and a plurality of corresponding logic gates (switches
32-38) which selectively include or exclude the passive elements. The examiner finds that Kalaf does not
specifically disclose that the feedback circuit is a decoder, but concludes that it would have been obvious
to use a decoder in view of the language "that various circuits are possible for effecting such switching in
direct response to the state of individual bits contained within the digital output word" (column 4,
lines 29-32).
Appellants' arguments are limited to the argument that Kalaf does not suggest any relevance to
trimming. These arguments are not persuasive for the reasons stated in the rejection over Merrick. Again,
appellants' reiteration of the limitations of claims 1, 8, 14, and 20 generally as not being met (Brief,
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