Appeal No. 2005-1869
Application No. 09/902,051
drive system for reading and writing information on a disk,
comprising a head to read/write information on the disk, a
preamplifier to amplify the information (identifying Figure 3,
element 100 for this teaching), and a read channel to process the
amplified information, wherein the read channel includes the
offset correction circuit to correct DC offset in accordance with
a data rate (identifying Figure 3, and “the remainder of 23" for
such a teaching). See page 2 of the answer.
Appellants’ arguments, in toto, comprises the following, at
pages 5-6 of the brief:
...Patti does not disclose or suggest the
presently claimed invention including a filter
circuit to respond to the thermal asperity signal in
accordance with the data rate.
The Examiner alleges that Patti discloses an
offset correction circuit to correct DC offset in
accordance with a data rate referring to Figure 3
element 102, Figure 2a, and column 6, lines 51-56.
Notwithstanding the allegations of the Examiner, Patti
discloses at column 6, lines 51-56 that the programmed
resistances of the variable resistance circuit 132 are
selected to achieve the cutoff frequencies for the
filter 112. The programmable thermal asperity recovery
circuit 132 provides flexibility allowing utilization
in read channels having potentially different or
varying characteristics (citing different data rates,
different causes for the thermal interference, etc.).
The resistance circuit 132 does not respond to
data rates.
3
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