Determination of laboratory standard microphone parameters in reciprocity calibration
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Typ
Examensarbete för masterexamen
Program
Sound and vibration (MPSOV), MSc
Publicerad
2020
Författare
Chen, Xuanzhu
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Reciprocity calibration is one of the most accurate technique to calibrate a primary
standard condenser microphone. The calibration procedure is conducted according
to IEC 61094-2:2009, including the calculation of acoustical transfer impedance,
electrical impedance as well as correction of thermal conduction, radial wave-motion,
and ambient pressure temperature. This paper investigates four characteristics of
laboratory standard microphone in reciprocity calibration, front cavity depth, equivalent
volume, resonance frequency, loss factor, and their influence on the pressure
sensitivity level. In order to obtain more accurate calibration results, microphone
parameters should be determined for every single laboratory standard microphone,
instead of using nominal values provided by the manufacturer in the reciprocity
calibration system. Several laboratory methods for every single microphone characteristic
are analyzed and the optimal solution is decided based on applicability, time
cost, and accuracy evaluation.
Beskrivning
Ämne/nyckelord
Microphone characteristics, Front cavity depth, Equivalent volume, Resonance frequency, Loss factor, Uncertainty