BRUEL & KJAER 1013 Instructions And Applications page 40

which is controlled from the Level Recorder Type 2305. The signal being
applied to the projector is applied from the BFO. The hydrophone is con-
nected to an amplifier, Microphone Amplifier Type 2604, which in turn is
connected to the Level Recorder. The Recorder has been loaded with Polar
Diagram Paper QP 5102. (See also Level Recorder Manual) .
By controlling the Turntable from the Level Recorder it is possible to run
it in synchronism with the paper drive motor. As the projector rotates, the
sound pressure at the hydrophone will vary in accordance with the directional
-..3"
5
0
0
<i
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~
2804
2804
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•
UB 0041
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1013
AOOOl
Standard Hydrophone
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Water
Hydrophone Projector
161780
Fig. 5.16. Measuring arrangement for automatic recording of the frequency
response of hydrophones.
38