Svantek SV 971A, Руководство пользователя

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SV 971A User Manual
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During the calibration measurement, the level of the measured calibration signal
is displayed. If the maximal difference between three consecutive 1-second LCeq
results is less than
0.05dB , the calibration measurement will be stopped, and the
calibration factor will be calculated. The measurement can be always stopped by
the
<Stop> key.
After calibration measurement stop, the Calibration drift (change of calibration
factor since last calibration, calculated in dB) is displayed and it will be proposed
to save the new calibration factor by pressing
<Enter> , or reject it by pressing
<Esc> . In both cases the instrument exits the Calibration screen.
It is recommended to repeat calibration measurements few times. Obtained results should be almost the
same (with

0.1 dB difference). Reasons for unstable results are as follows:
•
calibrator is not properly attached to the instrument,
•
there are external acoustic disturbances such as high noise levels nearby,
•
calibrator or measurement channel (microphone, preamplifier or instrument itself) is damaged.
Note: During the calibration measurement, external disturbances (acoustic noise or vibrations)
should not exceed a value of 100 dB (when using a calibrator that generates 114 dB).
5. Press <Enter> to accept and save the new calibration
factor.
To quit the calibration procedure without saving the
calibration factor, press
<ESC> .
<ENT>
Note: If calculated calibration drift is out of the
±3 dB range, the warning “
Microphone outside
the tolerance. Accept?
” appears on the screen.
If the calibration drift is out of the ±20 dB range,
the header of the screen turns red:
Calibration .
6. Detach the calibrator from the microphone.
3.2.2 Last calibration record
– Last Calibration
The Last Cal. screen displays the information regarding
recent calibration record for the current measurement
function: type of calibration (
Factory Calibration ,
By Sensitivity or By Measurement ), date of calibration
and calibration factor.
<ENT>
3.2.3 History of calibrations
– Calibration History
The Cal. History screen displays list of calibration
records which you can view by pressing the <Enter>
key.
<ENT>