Appeal No. 1998-2508
Application 08/626,299
switch 23-1 is turned on when the output from the band pass
filter 14 exceeds the standard level. During the time that
the switch 23-1 is turned on, the voltage sampled by the phase
comparator 22 is stored in the integrating circuit; whereas,
when the output of the band pass filter is lower than the
standard level, in other words in the ideal tracking
condition, the switch 23-1 is turned off and the voltage which
has been just stored in the capaci- tance 23-3 is applied to
the subtractor 24. Kimura discloses that in this manner, the
feedback loop is made operative only when the tracking error
is produced and thus the tracking control can be effectively
stabilized.
From these teachings of Kimura, we fail to find that
Kimura teaches converting light from a laser light source
which has been reflected from the storage medium into an
electrical signal and integrating that electrical signal over
a period of time which is equal to at least one period of the
recited oscillating motion. Kimura, on the other hand,
teaches that voltage memory 23 integrates a sawtooth signal
that is sampled at a particular time and does not teach
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