CASTLE GA112, Руководство пользователя

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Calibration
The calibrator recommended for use with the GA112 is the Castle
GA607, a dual level calibrator which supplies 94dB and 104dB
(relative to 20 uPa pressure) at a frequency of 1kHz.
Procedure
1 Turn ‘on’ the instrument by switching it into ‘A weighting’ mode
and check the conditions of the batteries by depressing the BATT
button.
2 Place the filter control switch in the OUT position, ideally the
response switch should be placed in the FAST position.
3 Turn the calibrator on to the 94dB and check that the battery status is
as per the calibrator manual. A 1kHz tone should be audible at this
time.
4 Position the calibrator firmly over the microphone using a
“clockwise” twist.
5 Place the meter on its 70dB range and adjust the CAL control until
the meter reads 94dB.
6 If using the Castle GA607 calibrator, it is also possible to check the
sound level meter on its 90dB range, switch the calibrator to the
104dB position and check that the reading is within 0.4 dB. This
serves as a cross check for the type 1 instrument.
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Two additional tests can be carried out in order to establish correct
calibration of the instrument. Firstly at the 1kHz calibration
frequency, switching the instrument to the LIN weighting mode, this
should give the same sound levels as the ’A’ weighting mode (within
1dB).
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