BRUEL & KJAER 2245 - Page 3

Sound Level Meter Types 2245 – Instruction Manual Page 3 of 110
3.4 Wi-Fi and Bluetooth during tests.............................................................. 37
3.5 Mounting for Acoustical Tests .................................................................. 37
3.6 Periodic Testing of Acoustical Frequency Responses ............................ 38
3.7 Mounting for Mechanical Vibrations Tests ............................................... 38
3.8 Testing 1/1-octave-band and 1/3-octave-band Filters ............................. 38
3.9 EMC Test Procedures ............................................................................. 38
3.9.1 Signal Sources for Immunity Test ................................................. 38
3.9.2 Reference Orientation ................................................................... 39
3.9.3 Securing of Cables During EMC Test ........................................... 39
3.9.4 Accessories Included in EMC Test ................................................ 40
3.9.5 Normal Mode of Operation During EMC Test ............................... 40
Chapter 4 Specifications ...................................................................................... 42
4.1 Specifications ........................................................................................... 42
4.2 Standards ................................................................................................. 42
4.3 Reference Environmental Conditions ...................................................... 42
4.4 Reference Conditions for Acoustic Calibration ........................................ 43
4.5 Microphone .............................................................................................. 43
4.6 Frequency Responses ............................................................................. 44
4.6.1 Electrical Frequency Responses ................................................... 44
4.6.2 Typical Low-frequency Responses ............................................... 45
4.6.3 Acoustical Frequency Responses ................................................. 46
4.6.4 Free-field Frequency Responses .................................................. 46
4.6.5 Diffuse-field Frequency Responses .............................................. 46
4.6.6 Free-field Frequency Responses for Diffuse-field
Calibrated Instruments .................................................................. 47
4.7 Directional Responses ............................................................................. 48
4.8 Self-generated Noise ............................................................................... 55
4.8.1 Maximum Broadband Self-generated Noise ................................. 55
4.8.2 Typical Broadband Self-generated Noise ...................................... 55
4.8.3 Typical Self-generated Noise Spectra ........................................... 55
4.9 Measuring Ranges ................................................................................... 56
4.9.1 Maximum Sound Level .................................................................. 56
4.9.2 Total Range ................................................................................... 56
4.9.3 Primary Indicator Range ................................................................ 57
4.9.4 Indicator Range ............................................................................. 57
4.9.5 Linearity Range ............................................................................. 57
4.9.6 Pulse Range .................................................................................. 58
4.9.7 Linear Operating Range ................................................................ 58
4.9.8 Peak C Range ............................................................................... 58
4.10 Detectors .................................................................................................. 59
4.10.1 Exponential Averaging ................................................................... 59
4.10.2 Linear Averaging ........................................................................... 60
4.10.3 Peak ............................................................................................... 60
4.11 Spectrum Analysis ................................................................................... 60
4.11.1 1/1- octave Band Centre Frequencies ........................................... 60
4.11.2 1/3-octave Band Centre Frequencies ............................................ 61
4.11.3 Linear Operating Range ................................................................ 63
4.11.4 Measurement Range ..................................................................... 63
4.11.5 Octave Band Time Constants........................................................ 63
4.12 Influence from the Operating Environment .............................................. 64
4.12.1 Environmental Stabilisation Time .................................................. 64
4.12.2 Temperature .................................................................................. 64
4.12.3 Humidity ......................................................................................... 64
4.12.4 Vibration......................................................................................... 64
4.12.5 Immunity to Power Magnetic Fields .............................................. 64
4.12.6 Immunity to Power and Radio-frequency Fields............................ 65