Appeal No. 20000-0717
Application 08/906,676
tracking filter in the intermediate frequency (IF) stage of a
frequency modulation (FM) receiver, the use of a divider would
be “counter-productive” [brief-page 8] since Rogers’ tracking
filter involves the rapid tracking of continuously frequency-
varying input signals, the frequency variation being
independent of the system in which the filter is used.
The examiner’s response, unconvincing to us, is to merely
contend that Rogers does not employ a frequency divider
because the frequency of the input signal from source 30 is
matched
with the operating frequency of the tunable band pass filter
30 and so the use of a frequency divider for matching the
input
frequency to the operating frequency of the tunable band pass
filter is considered to be a matter of design expedient for an
engineer.
Taking independent claim 1 as exemplary, and applying
Rogers’ disclosure, at Figure 2, thereto, we find that Rogers
does, indeed, disclose a phase locked filter comprising a
6
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Last modified: November 3, 2007