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r - - - - - - - - - - - - - - l n t e r f a c e
Auxiliary
Level Recorder
X-Y Recorder
BrUel &
Kjmr
Serial
No.
•
r
0
j
.
46
Made in Denmark
-
Not used
" 0":
IEEE Format
"1 "
:
Spec.
Format
"0
.. :
SR3=LF
A
EOI
" 1": SR3=
ETX
A
EOI
AS(MSB)
}
-
A 4
Device
:~
Address
G
A1
(LSB)
Fig. 8.
IEEE interface and output connections
.-----
--Generator
-
-- - - - - .
Fixed
Osc.
200kHz
7V .tt.90
e
Var.
Osc.
200
-
240kHz
7V
.tt.O
@
Ext.
Input
0
-
10V
Iii'
tii'
\91
-...:/
Fig. 9.
Generator input and
outputs
l
0
u
T
p
u
T
J
DIN sockets are also provided for
use with Level Recorder Type
2307,
X-Y Recorder Type 2308 and other
auxiliary 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 oscillator
output provide the necessary signals
for frequency tuning of a tracking fil-
ter, for example the Brtiel & Kjrer
Slave Filter Type 5888. The power
amplifier control signal can be taken
from either of·the two 0-10V outputs
situated on the front and rear panels.
The rear panel generator input and
output connectors are shown in Fig. 9.
Use With Other
Instruments
Swept Sine Excitation
Swept sine excitation is used for res-
Control Signal
Vibration Exciter
Control 1050
Power Amplifier
2707
Vibration Exciter
4801
+
Head
Fig.
10.
Instrumentation for swept
sine testing
and motion
analysis
of a
tes
t object
4
860253
~~;.
.
. .
..
•
Fig. 11
.
Slave Filter
Type 5888
onance searching in engineering devel-
opment and prototype testing,
envi-
ronmental testing and transducer cali-
bration. This testing technique uses a
controller to provide a vibration excit-
er with a control signal 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
qe
automatically adjusted if a
constant level of vibration is to be
maintained. This is attained 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, and an Acceler-
ometer Type 4384 is used to provide a
feedback signal to the Type 1050 for
compressor regulation of the vibration
level.
Filtering of Vibration Signals
The Brtiel & Kjrer Slave Filter Type
5888 is specially designed for use with
the Type 1050. It is a 2 channel slave
filter which enables simultaneous fil-
tering of the control and response sig-
nals.
Band pass filter bandwidths avail-
able are
3,
10, and 30% and selection
is by remote control from the Type
1050.
The Slave Filter Type 5888 is
shown in Fig. 11.
Erroneous regulation of the com-
pressor can be caused by harmonics
and noise. Use of a tracking filter
to-
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