Conformance testing
This chapter contains the information needed to conduct conformance testing according to the specified
standards.
Mounting for acoustical tests The microphone must be mounted on the preamplifier.
Electrical substitute for the microphone To obtain a BNC Class electrical input, the
microphone must be replaced by an electrical
microphone impedance ST 02 with the serial
capacitance 18 pF +/- 10%.
Note: For the conformance of electrical tests, the Microphone Compensation must be set to
โOFFโ! (path: <Menu> / Measurement / Compensation Filter).
Note: For the conformance of acoustical tests, the Microphone Compensation must be set
to โOnโ! (path: <Menu> / Measurement / Compensation Filter).
Periodical test upper frequency 8 kHz
Linear Operating Range
Table C.1.1. Linear operating range: for the sinusoidal signal and microphone sensitivity 50 mV/Pa
Note: For the signals with the crest factor n >1.41 upper measuring range of the RMS (LEQ
and SPL) is reduced. The valid upper limit can be calculated according to the below given
formula: ๐จ
๐
= ๐๐๐ โ ๐๐๐ฅ๐จ๐ โก(๐/
โ
๐), where A is the upper limit for the sinusoidal signal.
Example: For the crest factor n = 10 the upper limit is A
10
= 113 dB.
The starting point at which tests of level linearity shall begin is 114.0 dB.
Measuring frequency range of the acoustic pressure (-3 dB) 3,5 Hz รท 20 000 Hz.
Basic measurement error of the acoustic pressure < 0.7 dB (measured for the reference
conditions, see below).
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