20
SW-BA-e-2020
measurement
should be used. The
With calibration factor
calibration procedure
allows the user to manually adjust the calibration factor.
4.2.1 Calibration by measurement
Select the
By Measure
option and press the <Enter> button
to
enter this menu. See Chapter 7 for more details on the specified
calibrator and its corresponding adjustment values.
The calibration level can be adjusted between 0 dB and 199.9 dB.
Press the arrow keys <◄>, <►> and <▲>, <▼> to change the
calibration level and the <Start> key to start the calibration. When
calibration is complete, the new calibration factor is updated and the user can press
the <Enter>
or <ESC> key to
save or ignore the result. This menu also displays the
calibration history. Entries with the
M
symbol at the end indicate that the data set has
been calibrated using the
By Measurement
procedure.
4.2.2 Calibration with calibration factor
Select the
With calibration factor
option and press the <Enter>
button
to
enter the menu.
Users can manually adjust the calibration factor. Use the arrow keys
<◄>
, <►> to
select the factor number, use the arrow keys <▲> ,
<▼>
to
select the value, save it with the <Enter> key and return to
the last menu with the <ESC> key. An entry with the end
F
indicates that
the data set was calibrated with the method
With calibration factor.
4.2.3 Conversion of calibration factor and sensitivity
The sensitivity can be calculated with the following formulas. The calibration factor can
also be calculated from the sensitivity and entered directly into the sound pressure
meter.
Cal.F = 20 * log (Sens / 50) + offset
Sens = 50 * 10
((calibration factor offset) / 20)
Here is:
Cal.F
is the calibration factor in decibels (dB);
Sens
the sensitivity of the microphone in mV/Pa;
Offset
the calibration factor in decibels (dB). This value is the calibration result with
the method
By measurement
with a signal of 50 mV. This offset is the device-specific
deviation, which is different for each sound pressure measuring instrument.
4.2.4 Calibration by measurement
Calibration by measurement is the recommended calibration procedure using a sound
calibrator. KERN can supply sound calibrators of class 1 and 2 according to the
standards GB/T 15173-2010 and IEC60942: 2003.
Proceed as follows for calibration by measurement:
1.
Insert the microphone into the cavity of the calibrator as far as it will go; the
microphone must be tight.