Norsonic nor1217, Instruction Manual

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8 Chapter 4
Technical description
A typical level for the returned signal is 45 mV with
an excitation of 1 volt corresponding to a sound level
of 92 – 95 dB dependant of the microphone cartridge
capacitance. The signal may be used for verification of
correct operation of the cable and preamplifier. Even
a malfunctioning microphone may be detected since
this is normally accomplished by a change in the mi-
crophone capacitance. A very low signal is returned in
case of a short-circuit in the microphone.
A 200 V polarised microphone will show approxi-
mately 2 dB higher level if the 200 V disappear due to
the lost tension and thereby decreased capacity in the
diaphragm when the 200 V is off.
The sound analyser Nor140 has a build-in signal
generator that delivers the required signal for system
check. The signal is switched on/off from the instru-
ment menu. See separate description.
Pin 1, System
Check input
Pin 4,
Output
Pin 2,
Ground
Microphone cartridge 18pF
0,8pF