Appeal No. 1998-0817
Application 08/610,976
a disk drive system that embodies the invention and includes a
microprocessor 9 for controlling the overall operation of the
disk drive system, a read channel 10 for recovering data read
from the disk, a write channel 12 for writing data onto the
disk, an a digital phase locked loop 11 for providing a read
clock to the read channel 10 and a write clock to the write
channel 12, and a reference oscillator 13 connected to the
phase locked
loop 11 to act as the center frequency of operations of the
phase locked loop to which correction will be made. On pages
7 and 8 of the application, Appellant discloses that the speed
of the spindle motor of the disk drive system is monitored to
detect differences between the specified nominal speed to the
spindle motor and the actual speed of the spindle motor.
Microprocessor 9 generates a digital correction value for use
by the phase locked loop that would change the write clock
frequency of the phase locked loop so as to compensate for the
variation in the speed of the spindle motor.
Independent claim 14 is reproduced as follows:
14. An apparatus for generating an adjusted clock signal
having a frequency and phase based on format data in a record
stored on a rotating disk in a disk drive system, the
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