BRUEL & KJAER 2305 - Vibration Measurement and Recording

Fig. 6. 28 illustrates the directional characteristic obtained in a horizontal
plane . From the recording can easily be read the front-to-back ratio in dB
and the half-power-angle (3 dB) in degrees. The Level Recorder was supplied
with a 25 dB Range Potentiometer, and as the output from the fie ld strength
meter was a DC signal, the RECTIFIER RESPONSE of the Record er was set
to
"DC".
Recording of Vibrations.
In the field of mechanical vibrations the Level Recorder is an ideal
measuring instrument , for when combined with suitable vibration test
e
quipment the results can be automatically recorded as functions of time
or frequency.
Exciting Section
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1013
Mechanical connection
2114
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Cathode
Follower
332112 2113
2104
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L- ________________________________ -JI
L __________ Mea5uring.2e~~ __________ J
90
1618"6
Fig. 6.29. Measuring arrangement for frequency response calibration of
accelerometers.