Appeal No. 2002-1197
Application 09/131,167
In re Baxter Travenol Labs., 952 F.2d 388, 391, 21 USPQ2d 1281,
1285 (Fed. Cir. 1991) ("It is not the function of this court to
examine the claims in greater detail than argued by an appellant,
looking for nonobvious distinctions over the prior art.").
We find that Koski teaches the limitation that "filter
coefficients of said adaptive filter are updated only when a
prevailing value of the output signal of said microphone is
within a predetermined range of possible output signal values"
(claim 1), as interpreted. Koski discloses that echo cancelers
are known and usually employ an adaptive digital filter where the
parameters (coefficients) are updated whenever far-end speech
occurs (col. 1, lines 21-42). Koski teaches that an improvement
is to not update the filter coefficients during double talk to
overcome the problem of distortion (col. 1, lines 43-63), which
indicates that the prior condition was to always update the
coefficients for every signal, which is considered to meet the
limitations of claims 1, 13, 17, and 25, as broadly interpreted.
Because these are the only limitations argued, we sustain the
rejection of claims 1-4, 8-28, and 32-37.
IF the claims recited updating the filter coefficients only
upon the condition that the output signal of the microphone is
within a predetermined range of possible output signal values,
where the predetermined range was less than the total range of
possible output signal values, the examiner's rejection could not
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