Appeal No. 96-0517
Application 08/264,473
off during each recording operation (represented by signal
level 0 in Figure 23(A)), and the power for the recording
circuit (not shown) is turned off during each playback
operation (level 1 in Figure 23(A)) -- see Spec. at 3:21 to
4:10. If the rise or decay time of first stage amplifier 22
differs from that of gm amplifier 24, current spikes Ic1 and
Ic2 flow through capacitor 26, as shown in Figure 23(D) (Spec.
at 4:11 to 5:17). This has the effect of delaying the point
in time when the voltage across capacitor 26 is stable enough
to permit commencement of the next type of operation (Spec. at
5:17-20).
Appellants' specification notes that while it is possible to
shorten the charging/discharging time by increasing the gm
value of amplifier 24, that would also have the undesirable
effect of increasing the cut-off frequency of the low pass
filter (defined by the gm value of the gm amplifier and the
capacitance value of capacitor 26 ), thereby disabling 4
effective dc feedback (Spec. at 5:21-25). Appellants disclose
a number of other techniques for dealing with the capacitor
4Spec. at 3:9-13.
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