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2. 7. Frequency Characteristics
The frequency characteristics of the amplifier in the acceleration mode (no
integration) are given in Fig. 2.8. The frequency response of the integration
networks are given in Fig. 2.9.
2.8. Output Characteristics
When the preamplifier is operated from the ZR 0024 the maximum output voltage
and current available in position ACCEL. is
±
7 V
±
1 rnA
peak.
In VELOCITY
or Displacement positions the minimum Load impedance is 1 MQ. This limits
the high frequency performance when working into capacitive loads, as
Fig.
2.10 illustrates. However, when BATT. or EXT. POWER
are·
selected, the output
is taken from the power amplifier. In these positions the maximum output
voltage and current is
±
7 V
±
2.3 rnA thus reducing the loading restriction
considerably as shown in Fig. 2.11
.
2.9. Sensitivity
As explained under INPUT SELECTOR there are fixed gains of 0 dB and
- 40 dB, and variable gains from 0 to
-
40 dB available. The voltage sen-
sitivity of B
&
K
acce·
l erometers, with cable, is given in the calibration chart
supplied with unit. If a different cable is used, the sensitivity is changed, and
becomes
where
Sv is the calibrated sensitivity
12
OJo
C1
is the accelerometer capacitance (without cable)
c.
is the cable capacitance used when Sv was measured
C.1
is the new cable capacitance
Distortion
5
(28V Power Supply}
3
2
2nd. harmonic - -
3rd. harmonic - - -
o~--~--~--~~~~~~---r=-~--+---~-4~
0
1
2
3
4
5
6
7
8
9
10V
RMS Output Voltage
..;?6"7/~-o
Fig. 2.12. Distortion for 0 dB and 20 dB gain.
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