BRUEL & KJAER 4184-A, Техническая документация инструкция, Страница: 16 / 52

Weatherproof Microphone Unit Type 4184-A – Supplement to Instruction Manual BE 1712 10
Fig.4.10 Both reference directions, Diffuse-field frequency response for Weatherproof Microphone Unit Type 4184-A
and the analyzer’s electrical response with the Microphone Preamplifier connected to a microphone extension
cable. Corresponds to the “Acoustical Response” column in Table A.8
Fig.4.11 Weatherproof Microphone Unit Type 4184-A is not specified together with Outdoor Microphone Kit UA-1404
4.7 Directional Responses
This section gives directional responses for plane progressive sinusoidal sound waves normalised to the
response in the reference direction. The directional responses are given as tables in Appendix A.
The sensitivity variation graphs show the absolute maximum difference between the sensitivities at any
two sound incidence angles within the specified interval of angles. For example, at each frequency the
value for ±30° is the difference between the highest and the lowest sensitivity found in a circular cone with
an opening angle of 60°, the top at the Microphone Reference Point and with the reference direction of
incidence as the axis. Because the angle interval defines a three-dimensional geometric shape there is only
one set of graphs with sensitivity variations, also where the directional response is shown for two planes.
The graphs show the maximum variation for the two measurement planes combined. The sensitivity
variations are also given as tables in Appendix A.
Limit curves are drawn on the sensitivity variation graphs in the following sections. These curves
represent the IEC 61672–1 limits, reduced by the ‘Maximum Expanded Uncertainties of Measurement’
from Appendix A of IEC 61672–1. The ‘Maximum Expanded Uncertainties of Measurement’ used here
are the maximum uncertainties that a test organisation may have on its measurements when it performs
conformance tests according to IEC 61672.
Fig.4.12 Weatherproof Microphone Unit Type 4184-A is not specified without windscreen
Fig.4.13 Weatherproof Microphone Unit Type 4184-A is not specified without windscreen
Fig.4.14 Weatherproof Microphone Unit Type 4184-A cannot be mounted directly on the analyzer
Fig.4.15 Weatherproof Microphone Unit Type 4184-A cannot be mounted directly on the analyzer
Fig.4.16 Weatherproof Microphone Unit Type 4184-A cannot be mounted directly on the analyzer
100 1000 10000 Hz
-4
-2
0
2
4
dB
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