Appeal No. 1999-1449
Application 08/640,351
the sample rate. This is accomplished by an interpolation
circuit C106 which computes an interpolated error value ek
C112 from the baud rate error values ek +t C104. Preferably,
the error value interpolation circuit C106 is implemented as
a first order linear interpolation, but it may be a simple
zero order hold, or a more complex interpolation filter as
described above.
Thus, the claim does require that the interpolation circuit
(C106) synchronize the error values e(k) to the channel sample
values X(k) (25), the claimed discrete-time sample values.
We agree with Appellants that Nowak does not teach or
suggest an interpolation circuit, which interpolates the error
value e(k) in order to synchronize the error values e(k) to the
channel sample values Xk, as claimed. We note that Nowak’s input
sample values are already synchronous to the error values. Nowak
discloses an adaptive control system 39, which includes an
adaptive control filter 46 for outputting a correction signal Yk
in response to an input signal Xk. The adaptive control filter
further includes an error sensor 54 for generating an error
signal e(k) to adapt the adaptive control filter. See Nowak,
column 3, lines 18 through 35. Thus, Nowak is not concerned with
the problem that Appellants’ invention seeks to resolve.
Specifically, Nowak does not seek to compensate for parameter
variations while reading data across the radii of a magnetic
disk. Hence, Nowak does not have a need to synchronize the input
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