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~--------------------------Interface--------------------------~
Auxiliary
Level Recorder
X-Y Recorder
Briiel & Kjaer
Serial No.
i 2
Jo
~
46
Made In
Denmark
Fig. 8. IEEE interface- and output-connections
....------Generator-------,
Fixed Osc. 200 kHz
7V ..:::90
Var.
Osc. 200-240 kHz
7V ...:::0
Ext.
Input
0-10V
+
@
Fig.
9.
Generator-input and -outputs
l
0
u
T
p
u
T
J
el at periodic intervals. It can also
print out the test parameter values.
DIN
sockets
are provided for use
with Level Recorder Type 2307, X-Y
AO 0087
AO 0231
Not used
"0
":
IEEE Format
"1 ": Spec.
Format
"0": SR3=LF
/1.
EOI
"1":
SR3=ETX
A
EOI
A5
(M SB) }
-
A
4
•
Device
:~
Address
A1
{LSB)
Recorder Type 2308 and other auxilia-
ry equipment.
These
sockets
are
shown in Fig. 8.
Generator outputs
Two constant-voltage outputs with
0° and 90° phase are available for use
with a multiplier. The multiplier can
output the real- and imaginary-parts
of a response signal for producing Ny-
quist plots. The 200kHz fixed-oscilla-
tor and 200-240 kHz variable-oscilla-
tor output provide the necessary sig-
nals for frequency tuning a tracking
filter, for example the Brtiel & Kjrer
Slave Filter Type 5888. The control
signal
for a power amplifier is avail-
able from the 0-10 V outputs situated
on
the front and rear panels. The rear-
panel generator input- and output-
connectors are
shown
in Fig. 9.
Control Signal
Vibration Exciter Control
1053
Power Amplifier
2707
Vibration Exciter
4801
+
Head
870420
Fig.
10.
Instrumentation for
swept-sine
testing and motion analysis
of
a
test
object
4
o..-
, _ _
9
•
•
•
--
Fig.
11.
Slave Filter Type 5888
Use with other
instruments
Swept-sine excitation
-
Swept-sine excitation is used for
resonance searching in engineering de-
velopment, prototype testing, environ-
mental testing and transducer calibra-
tion. This testing technique uses sinu-
soidal vibration which changes in
frequency between certain limits at a
pre-determined sweep rate.
Resonances of the test object and
exciter system cause the power sup-
plied to the exciter to be frequency
dependent. Consequently, the signal
must be automatically adjusted if a
constant level of
vibration
is to be
maintained. This is achieved by using
a control accelerometer, mounted on
the exciter table or test
specimen,
in a
servo-loop
to provide a feedback sig-
nal to the compressor section of the
controller. The compressor regulation
speed is chosen according to the ex-
pected Q-values of the system reso-
nances and the sweep rate used during
the
test.
An
instrumentation
set-up
for
swept-sine
testing is shown in Fig. 10.
The Digital Stroboscope Type 4913 is
used for analyzing the vibratory mo-
tion of the test object. The Accelerom-
eter Type 4384 is used to provide a
feedback signal to the Type 1053 for
compressor regulation of the vibration
level.
Filtering vibration signals
Erroneous regulation of the com-
pressor can be caused by harmonics
and noise. By using a tracking filter
with the controller, the feedback sig-
nal is assured free from noise and con-
trolled by the excitation frequency
alone.
The Brtiel & Kjrer Slave Filter Type
5888 is especially designed for use
with the Type 1053. It is a two-chan-
nel slave filter, enabling simultaneous
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