GRAS 46AD Micrô đo lường 1/2" CCP Pressure

1. Introduction

The 46AD is a pressure microphone set and as such optimized for acoustic measurements of the sound source in a closed coupler or the measurement of sound pressure at a boundary or wall; in which case the microphone forms part of the wall and measures the sound pressure on the wall itself.

The medium frequency range makes it ideal for general acoustic diagnostics.

Regarding temperature range, see the Specifications. Should higher temperature limits be required, we recommend considering the GRAS probe microphones where the microphone and preamplifier can be isolated from the hot source.

A front-vented version is available, 46AD-FV 1/2" CCP Pressure Standard Microphone Set, Front Vented.

2. Key Features

2.1. Design

The GRAS 46AD is a high-performance standard microphone set. In our clean-room environment the set is assembled and sealed with a label. However, the microphone set can be dismounted, if you wish to use the components separately.

Microphone
The microphone cartridge is the high-quality IEC 61094 WS2P standardized GRAS 40AD 1/2" Prepolarized Pressure Microphone, High Sensitivity, designed for long-term reliability in multiple environments.

Preamplifier
The preamplifier is the GRAS 26CA Preamplifier which is inclusive TEDS and based on our well-known circuit board substrates. In the industry these are famous for their low self-noise, wide frequency and excellent slew rate performance.

2.2. Compability

To perform as specified, the GRAS 46AD microphone set requires a constant current input module that can deliver 4 mA and 24 V unloaded CCP voltage supply. If the constant current supply is lower, the capability of driving long cables is reduced and consequently the upper frequency is reduced. If the voltage supply is lower it will influence the upper dynamic range.

The microphone set is terminated with a BNC connector. Cables with BNC connectors of various types and lengths are available in standard as well as customized lengths.

The 46AD is IEEE 1451.4 TEDS v. 1.0 compliant. If your measurement platform supports Transducer Electronic Data Sheets you will be able to read and write data like properties and calibration data.

2.3. System verification

The functionality of TEDS is very useful to determine which microphone is connected to which input channel. However, it is not a check of whether the microphone is within specifications or not. For daily verification and check of your measurement setup, we therefore recommend using a sound source like the GRAS 42AG Sound Calibrator.

For proper sensitivity calibration we recommend using a reference sound source like the GRAS 42AP Intelligent Pistonphone.

2.4. Service

Should you by mistake damage the diaphragm on a GRAS microphone we will in most cases be able to exchange it at a very reasonable cost and short turn-around time. This not only protects your investment but also meets your quality assurance department since you do not have to worry about new serial numbers etc.

2.5. Calibration

When leaving the factory, all GRAS microphones have been calibrated in a controlled laboratory environment using traceable calibration equipment. Depending on the use, measurement environment and internal quality control programs we recommend that the microphone is recalibrated at least once a year.

We offer two kinds of calibration as an optional after-sales service: GRAS Traceable Calibration and GRAS Accredited Calibration.

GRAS Traceable Calibration is a traceable calibration performed by trained personnel under controlled conditions according to established procedures and standards. This is identical to the rigorous calibration that all GRAS microphones are subjected to as an integral part of our quality assurance.

GRAS Accredited Calibration is performed by the GRAS Accredited Calibration Laboratory that has been accredited in accordance with ISO 17025 by DANAK, the Danish Accreditation Fund.

If you want a new microphone set delivered with an accredited calibration in stead of the default factory calibration, specify this when ordering.

3. Specifications


Polarization/Connection	0 V / CCP
Frequency range (±1 dB)	12.5 to 7.5 kHz
Frequency range (±2 dB)	3.15 to 10 kHz
Dynamic range w/ GRAS CCP preamplifier	18dB (A) to 138dB
Set sensitivity	50 mV/Pa (-26 dB re 1V/Pa)
Output impedance	< 50 Ω
Output Voltage Swing, min. @ 24-28 V CCP voltage supply	8 Vp
Power supply min. to max.	2 to 20 mA
Power supply min. to max. (single/balanced)	N/A
DC bias voltage, typ.	12 V
Microphone venting	Rear (Front on request)
IEC 61094-4 Designation	WS2P
Temperature range, operation	-30 to 85 °C
Temperature range, storage	-40 to 85 °C
Temperature coefficient @250 Hz	-0.01 dB/°C
Static pressure coefficient @250 Hz	-0.01 dB/kPa
Humidity range non condensing	0 to 90 % RH
Humidity coefficient @250 Hz	-0.001 dB/% RH
Influence of axial vibration @1 m/s²	62 dB re 20 µPa
TEDS UTID (IEEE 1451.4)	27 v. 1.0
Connector type CE/RoHS compliant/WEEE registered Weight	BNC Yes/Yes/Yes 33 g
Dimension	84 x 13.2 mm