Norsonic nor1217, Инструкция по эксплуатации

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7 Norsonic Nor1217
Instruction Manual
The supply voltage will affect the maximum sound pres-
sure that can be measured. For ±15 V or +30 V supply,
the maximum peak value exceeds 10 volt corresponding
to 140 dB peak sound pressure level for the Nor1227 /
Nor1225 microphone cartridge (50mV/Pa).
By the use of the “high level” option in Nor140, signals
with peak values up to 150 dB may be measured with
the microphone cartridge Nor1225.
The figure below shows a simplified electrical circuit
diagram of the complete outdoor microphone. The
microphone cartridge is connected to the preamplifier
input terminal. The figure below shows the output con-
nector seen from outside.
1
2
3
4
5
7
6
Signal ground
Polarization voltage
Signal output
Not connected
Power
Power supply -
5
6
1
4
3
7
2
V+
NC
System check
Output
Heater
resistor
V
pol
V-
GND
System check
The system check terminal, pin 1, shall be termi-
nated to signal ground or the signal output when the
microphone system is in normal use. For checking the
system, a test signal may be supplied, e.g. an AC sig-
nal of 1 volt – 1000 Hz. The signal is transmitted to the
preamplifier input through a capacitor with a very low
capacitance (about 0.8 pF) and further to the signal
output.
The system check is a robust and simple method
for verifying a microphone system. It measures the
change in the capacity of the microphone cartridge.
Nominal cartridge capacity of a ½” microphone is
18 pF. The test signal is feed through a fixed 0,8 pF
capacitor, and the system check voltage is measured
as a function of the attenuation between the 0,8 pF ca-
pacitor and the microphone cartridge with a nominal
capacitance of 18 pF.