HBK Sound Calibrator Type 4231 Bedienungsanleitung Seite 23

Chapter 3 – Characteristics
Fig.3.3 Cross-section of the calibrator
Microphone to be calibrated
Fig.3.4 shows a block diagram that illustrates how the calibrator's
electronic circuit works. The main components of the diagram are
described in the following sections.
Fig.3.4 Block diagram illustrating the principle of the calibrator's operation
Microphone
to be
calibrated
Coupler
3.8.1 Feed-back Circuit
The signal from the microphone is fed to the feed-back circuit. The
feed-back circuit contains:
• a band-pass filter
• a temperature compensation circuit
• a detector
Loudspeaker
Pressure Equaliza on Channels
Feed-back
Circuit
Variable
Amplitude
Sine Generator
Sound Calibrator Type 4231
User Manual
1/2" Adapter
Reference Microphone
SPL
Reference
Overload
Gain
Frequency
Reference
Ba ery
Lid
Circuit Board
930129/1
On/Off
Control
Circuit
+20 dB
930192/1
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