B&K 2250 Light Manuel d'utilisateur télécharger pdf (Page 47)

Chapter 5

Calibration

5.1 Introduction

Calibration is an adjustment of your sound level meter to measure and display correct values.

The sensitivity of the microphone as well as the response of the electronic circuitry can vary

slightly over time, or could be affected by environmental conditions such as temperature and

humidity. While you are unlikely to ever experience a large drift or change in sensitivity with

the analyzer, it is nevertheless good practice to perform regular calibrations, normally before

and after each set of measurements. Often calibration is required by measurement standards,

such as IEC 61672–1.

If you want your analyzer to remind you when the next Accredited/Traceable calibration is due,

you can set it up on the Reminder tab of the Calibration screen. See section 5.6.

You can check the complete measurement chain during long-term measurement using Charge

Injection Calibration. See section 5.7.

5.2 Calibration Types

Acoustic Calibration

Acoustic calibration is the preferred calibration method, particularly when standards and

regulations require calibration before a measurement. The method involves applying an

acoustic signal of known magnitude and frequency to the microphone, which calibrates all the

instrument’s components (microphone, preamplifier and electrical circuitry).

Electrical Calibration

If no sound level calibrator is available (or a known amplification is introduced, i.e., by

analyzing a tape recorded signal) then you can type the sensitivity directly into the Sensitivity

field. The analyzer will be regarded as uncalibrated, and the text ‘Uncal.’ will appear in the

status field.

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B&K 2250 Light Manuel d'utilisateur Page 47