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on the response of the preamplifier when various lengths of cable (shunt
capacitance 5 n F /1 00 m) are connected to its output.
5.2.4. Frequency and Phase Characteristic of Integration Networks
For measurements of vibration velocity the 4292 contains 3 single
R-C
integration networks, whilst for measurements of vibration displacement, 6
double
R-C
integration networks are employed. The frequency and phase
characteristics of the velocity networks are shown in Figs. 5. 7 and 5.8
respectively, vyhilst those for the displacement networks are shown in
Figs.5.9 and 5.10 respectively.
When using these networks for vibration measurements, a network
should be chosen which has a lower limiting frequency (-7 dB on velocity
characteristics given in Fig.5. 7 and -14 dB on displacement characteristics
~
~
~ .
~
Vel6city
J
~
.............::
-............::
1:
1 Hz
-
3
m
/sec.
-
~
~
2:
10
Hz
-
0.3 m
/
sec.
3
:
100
Hz
-
0.03/sec. _
~
~
~
~
~
"
""'
~
""
~
~
-30
~
~
['{
"' r --....
""""'
"""!'..
~
~
~
""'
I""'
I""
-
40
-50
~
~
1
Hz
10H
z
100Hz
1
kHz
10kHz
Frequency
2 Tt'P/9
Fig.5.7. Frequency response of velocity network
V~locity
I_
---
---
1:
1
H
z
-
3
m/set.
.............
..............
2:
10 H
z
-
0
.3
m/sec.
-
3:
100
Hz
- 0.03/sec.
"'
"'""-.
i'-..
""\.
"'
""\.
-
50
"1'\.
1
~
2
'~
3
""'
"
~
~
!'--..
f'..._
.._____
1---
....___
-
60
-
70
-80
-
90
0.1
Hz
1
Hz
10 Hz
100Hz
1
kHz
Frequency
2TI'218
Fig. 5. B. Phase response of velocity networks
26
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