BRUEL & KJAER 1022 Instructions And Applications page 37

ooooooooooooooooooooooooooooooooooooooooooooooooooo
lrO:!.!.!I•r+
-
""- -"""'-
w. ...
_ s...: _
_ _ ,....Sc-.._
10
QP 0123 10 100
211110 WI . - A I C L-.
~
.. ,.,.A •
c
la
f6(070
Fig.5.15. Reading obtained with a set-up as in Fig. 5.14.
50 dB range potentiometer used in Level Recorder
A set up is shown in Fig.5.16. where a compressor loop is used to keep
the sound level constant. The feedback signal is amplified by a Measuring
Amplifier 2606. Another 2606 is used in conjunction with the 2020 to
analyze the attenuated signal in the receiving room. The analyzed signal is
then recorded on frequency calibrated paper using a Level Recorder 2305
and thus provides a direct measure of the sound insulation qualities of the
room at any frequency in the measuring range.
1022
Source Room
Receiving Room
4145
Measuring Amplif ier
2606
100-120kHz
120kHz
level Recorder
2305
17oo lf7
Fig.5.16. Set-up for measurement of airborne sound insulation
using a Heterodyne Slave Filter 2020
37