BRUEL & KJAER 4226 User Manual page 19

•
Sound Level dB:
Use this switch to select the sound level (within the tolerances given in Appendix A) you want
to check the calibration of your instrument:
– 94: A properly calibrated instrument with linear frequency weighting should read within
its frequency range, and within its tolerances, 94 dB at all selected discrete frequencies.
– 104: A properly calibrated instrument with linear frequency weighting should read within
its frequency range, and within its tolerances, 104 dB at all selected discrete frequencies.
– 114: A properly calibrated instrument with linear frequency weighting should read within
its frequency range, and within its tolerances, 114 dB at all selected discrete frequencies.
– 94 Inv. A.: A properly calibrated instrument with A-weighting should read within its
frequency range, and within its tolerances, 94 dB at all selected discrete frequencies.
•
Timer:
Used to calibrate dose meters, where a coupler signal with a well-defined level and duration
is required. The Function switch must be set at Calibration. 30 seconds after pressing this
button, the selected Sound Level in the coupler will be switched off. During this period the On
LED lights up and all other switches are inhibited. At the end of this period the LED flashes
signifying that the sound level is switched off. At this point you may press the Timer button
again to restore the selected Sound Level and uninhibit the other switches.
The Timer facility may be cancelled at any time during this 30-second period by pressing the
Timer button again.
To find out more about calibrating noise dose meters, see section 3.9.
The Parts of Multifunction Acoustic Calibrator Type 4226
CHAPTER 2
11