Appeal No. 97-3918
Application 08/447,901
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the
examiner's rejection of claims 2 and 9 under 35 U.S.C. §§
102(b) and 103. The remaining application claims, i.e.,
claims 1, 3-8, and 10-18, were withdrawn from consideration by
the examiner as directed to a nonelected species in paper No.
9. We reverse both rejections.
The invention is a playback circuit for a magnetic head
of the magneto-resistive (MR) type. The prior art playback
circuit shown in appellants' Figure 22, described in the
specification at 2:24 to 3:20, includes a first-stage
amplifier transistor 22 having its collector connected to one
input of a differential-input gm amplifier 24, which functions
as a voltage-to-current converting amplifier. The other input
of gm amplifier 24 is connected to a source 25 of reference
potential. The output of gm amplifier 24 is connected to one
side of a capacitor 26, the other side of which is connected
to ground. The output of gm amplifier 24 is also connected in
a feedback path to the base of transistor 22. In order to
conserve power, the power for the playback circuit is turned
off during each recording operation (represented by signal
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