Interacoustics AT235 Service Manual page 28

Service Manual
AT235
CALIBRATION OF DD45
Equipment needed for DD45 calibration
Measuring amplifier
•
Acoustical IEC 60318-3 (IEC 303) coupler
•
• Frequency counter
Correction values for coupler
•
From the AUD menu, select Transducer Calibration.
Place the transducer on the 6cc IEC 60318-3 (IEC 303) coupler
Adjust the slider until the calibration level is obtained on the measurement amplifier
(i.e. 90 dB SPL).
Fig 43
Check the frequency accuracy with a frequency counter. The accuracy has to be better than ±1%.
When the intended calibration level is obtained, use 'Enter' to get the next frequency.
Repeat until all stimuli are calibrated, for both the left and right transducer.
NOTICE
Do not forget to add or subtract the correction for your microphone
Fig. 42
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