Larson Davis SoundAdvisor, Справочное руководство

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SoundAdvisor Model 831C Understanding the Calibration Process 5-1
Module 5 Calibrating Your SoundAdvisor 831C
In this module:
5.1 Understanding the Calibration Process .............................................................................5-1
5.1.1 Determining Microphone Sensitivity ...................................................................5-1
5.1.2 Determining Noise Floor, Overload, and Under Range Levels ...........................5-1
5.1.3 Understanding Calibration Stability ....................................................................5-2
5.2 Reviewing the Calibration Settings ....................................................................................5-2
5.2.1 Calibrate Tab .........................................................................................................5-3
5.2.2 Calibration Settings Tab .......................................................................................5-3
5.2.3 Calibration History Tab ........................................................................................5-3
5.2.4 Calibration Certification Tab ................................................................................5-4
5.3 Choosing a Calibrator .........................................................................................................5-5
5.4 Calibrating Your SoundAdvisor 831C .................................................................................5-5
5.1 Understanding the Calibration Process
5.1.1 Determining Microphone Sensitivity
The primary role of sound level meter calibration is to establish a
numerical relationship between the sound level at the diaphragm of
the microphone and the voltage measured by the meter so that the
sound pressure level can be read directly from the display of the meter
in dB. The result of a calibration is the determination of the sensitivity
of the meter, including microphone and preamplifier, typically in dB re
1V/Pa or mV/Pa.
5.1.2 Determining Noise Floor, Overload, and Under Range Levels
A secondary role of calibration is to determine the sound level which
would overload the instrument (Input Overload level) and the
minimum sound level (Under Range level) that can be accurately
measured without being influenced by the operational noise from the
meter (Noise Floor).
Noise Floor Level
The noise floor is calculated as the energy sum of the noise generated
by the microphone, preamplifier, and instrument circuitry. The
appropriate noise floor, and nominal sensitivity compute automatically
in the 831C with the following preamplifiers and their commonly paired
microphones:
• PRM831
• PRM2103
• ICP with ADP074