Norsonic nor103, Инструкция по эксплуатации

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10 Chapter 3
Calibrating the instrument
2. Mount the calibrator. Mount the sound calibrator onto the microphone. Switch
on the sound calibrator and wait until the level has stabilized, according to man-
ufacturer’s product manual or at least for a minimum of 30 seconds.
3. Adjust the dB value . Press the
START/STOP
key (Down) or
MODE
key (Up)
to adjust the display volume to 94 dB if calibrator output is 94 dB or 114 dB if
calibrator output is 114 dB.
Know the output level of your sound calibrator.
Some sound calibrators have an output level of 94 dB, while others have an output
level of 114 dB. Norsonics Nor1256 will be able to give both signals.
Unless you know the output level of your sound calibrator you won’t be able to know
what level the measuring instrument is supposed to show. The output level is normally
stated on the sound calibrator or in its accompanying user documentation or calibra-
tion certificate.
NOTE! Be aware of the fact that instruments using free-field Microphones, like Nor103,
shall sometimes be adjusted to a value slightly lower than the output level of the sound
calibrator. For this half-inch cartridge this will typically amount to 0.2 dB lower for
calibrators producing a 1000 Hz calibration signal (e.g. the sound level meter should
then be set to 113.8 dB when using a 114 dB @ 1000 Hz sound calibrator).
The internal calibration (calibration with an electronic signal) can be chosen. Such
calibration is not according to standard IEC 61672-1, but to be considered a perfor-
mance check or self-test.
For adjusting the instrument with the built-in oscillator (1 kHz, sinusoidal wave), you
press the
A/C/CAL
key to switch to the internal calibration screen. “Int”, “Cal”, and
“94.0dB” will appear on the display.
The frequency weighting characteristic is fixed to C and the time weighting characteristic
is fixed to F. The display will look as shown on the figure.
Then just press the START/STOP key (Down) or MODE key (Up) to adjust the volume
to 94.0 dB.