Microphone Calibration System 90CA
Product Data
The G.R.A.S. 90CA Microphone Calibration System provides for automated and reliable level and frequency response calibration of measurement microphones. The implemented calibration methods conform with relevant standards as listed in the specifications.
Main Features
Highly automated and computer-controlled calibration process Accurate calibration hardware Ready-to-use software and hardware Preinstalled test parameters for G.R.A.S. microphones and microphone sets Optional software for test of preamplifiers Easily changeable test conditions Highly reproducible calibration method Auto-generated, customized documentation for printing and archiving
Typical Applications
Calibration of All types of IEC61094 standardized , , and 1 measurement microphones from G.R.A.S. and other manufacturers G.R.A.S. 46xx series microphone sets G.R.A.S. preamplifiers Calibration up to 92 Hz
Fig. 1 A typical setup for the Microphone Calibration System 90CA
Microphone Calibration in Four Easy Steps
The 90CA Microphone Calibration System is designed to eliminate the risk of operator error during calibration. This makes the workflow simple and straight-forward. The four basic steps are:
Vers. 1 March 2012
G. R . A . S.
SOUND & VIBRATION
Skovlytoften 33, 2840 Holte, Denmark www.gras.dk gras@gras.dk
Microphone Calibration System 90CA
Step 1: Microphone Registration
Meteorological data (test conditions) and microphone parameters (sensitivity, frequency response, tolerances, etc.) are entered into the system. For G.R.A.S. microphones, the system features a built-in database containing calibration parameters (sensitivity, frequency response, tolerances, etc.) The database can easily be extended to include microphone types of other manufacturers.
Step 2: Level Calibration
Using a pistonphone and an insert-voltage preamplifier, the open-circuit sensistivity of the microphone is determined at 250 Hz, 114 dB. The open-circuit sensitivity is displayed in [dB re 1 V/Pa] and [mVPa]
Pistonphone Auto-ON/OFF Static air pressure Microphone Definition File Level Calibration: - Pistonphone level and frequency - Test specifications (open-circuit sensitivity [max;min])
G.R.A.S.
G.R.A.S.
Power Module Type 12AQ Channel 1
Overload Gain in dB
10 0 -10 -20 20 30 40 50 60 70 -10 -20 0
Spring arrangement
Preamplifier Type 26AG
Power Battery Remote
RA0192
PXI Cards Control Card Calibration Software SW0002
Channel 2
Latch Overload Gain in dB
10 20 30 40 50 60 70
Extended Frequency Range
Microphone to be calibrated
Preamp. Pistonphone
Preamp.
Insert Active Polarization
Filter
HP Lin AW Ext Lin HP
Filter
AW Ext
Preamp. Actuator Stand
Preamp. Test Input
CCP Input
Pistonphone Type 42AP
G.R.A.S.
Pistonphone
Data Aquisition Card
Floating Output Polarization 0V Preamp. 15V SysCheck
Input Adapter
Signature Series
Power Module Type 12AQ
Control Box RA0192
Pistonphone Calibration Stand AL0017
Microphone Calibration File Output for Level Calibration: Open-circuit Sensitivity - Level [mV/Pa] - Pass/Fail indication
Level Calibration Equipment
Signal Conditioning, Power, and Switching
System Controller
Fig. 2 The setup for the level calibration with the pistonphone and an insert-voltage preamplier
Step 3: Frequency Calibration
The default frequency range is set individually for each type of microphone (range 200Hz to 92kHz). The default relative frequency step size is 1/6 octave with no minimum relative step size. The magnitude response for each calibration frequency has an accuracy of 0.003dB. The frequency range and steps are customizable.
R.A.S G.
A0
014
Electrostatic Actuator RA0014
Microphone for calibration
Adapter Preamplifier 26AB (inside calibration stand) Actuator Calibration Stand AL0010
Microphone Definition File Frequency Response - Test frequencies (1/6 octave stepping) - [Max;min] for each test frequency
G.R.A.S.
Actuator Supply Type 14AA
Po we r On
Frequency Calibration Equipment
Fig. 3 The setup for the frequency calibration
.
G.R.A.S.
G.R.A.S.
Power Module Type 12AQ Channel 1
Overload Gain in dB
AC Input Max. 1Vrm s Overload
-10 -20 10 0 20 30 40 50 60 70 -10 -20 0
Power Battery Remote
RA0192
PXI Cards Control Control Card Card NI6503 Calibration Software SW0002
- A dapter AF 000 8
G.R.A.S.
Channel 2
Latch Overload Gain in dB
10 20 30 40 50 60 70
Extended Frequency Range
Preamp. Pistonphone
Preamp.
Insert Active Polarization
Filter
HP AW Ext Lin HP
Filter
AW Ext
AC Output
AC Output +80 0VD C
Lin
Preamp. Actuator Stand
Preamp. Test Input
CCP Input
Data Acquisition Card
AC Output +20 0VD C
Floating Output
GND
Preamp. 15V
Polarization 0V SysCheck
Input Adapter
Signature Series
Actuator Supply 14AA
Power Module
Control Box
Microphone Calibration File Output for Frequency Response: - Level (magnitude [Pa] and phase) - Pass/Fail indication
Signal Conditioning
System Controller
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Microphone Calibration System 90CA
Step 4: Calibration Certificate
All the calibration data is saved as a text file; it contains results for both the level and the frequency calibrations. The system generates a calibration certificate that can be saved as a PDF file for archiving and printing. You can fully customize the certificate with your company layout, text, and logo, as well as which data to display.
CERTIFICATE OF CALIBRATION
Page 1 of 2
Frequency Response [dB]
-0.8 -0.9 -1 -1.1 -1.2 -1.3 -1.4 -1.5
1 10 100 1000 10000 100000
Freq [Hz]
Calibration Laboratory: G.R.A.S. Sound & Vibration Skovlytoften 33 2840 Holte Denmark Phone: +45 45664046 Calibration System made by G.R.A.S. Sound & Vibration, Denmark
Fig. 4 Typical G.R.A.S. calibration certificate
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Microphone Calibration System 90CA
Ordering Information
The 90CA microphone calibration system is sold as a complete package. Special options are available for specific types of calibration, accredited calibration, and training. The contents of the 90CA package are listed here for your convenience.
Options
OP0020: Preamplifier Calibration Option Pressure microphone, prepolarized Preamplifier with 3m cable CCP preamplifier CCP preamplifier with 3m cable (Microdot connector) 20pF Input adapter for preamplifiers 3m LEMO extension cable for preamplifier 3m microphone cable, SMB-BNC connector 1m Cable BNC 50ohm Test program for preamplifier OP0021: Calibration of 1 Microphone Option Adapter for 1 microphone and preamplifier 1 Electrostatic actuator OP0022: Accredited Calibration of Reference Units DANAK calibration of reference microphone, reference preamplifier, and pistonphone (contact your G.R.A.S. representative for details) TR001: Training Contact your G.R.A.S. representative for details
The Microphone Calibration System 90CA Package
Instruments Pistonphone including control cable Preamplifier (including adapter for microphones) Insert Voltage Preamplifier Preamplifier (for non-G.R.A.S. microphones) Insert Voltage Preamplifier Power Module (incl. 12VDC adapter) Actuator Amplifier (incl. 230VAC power cable) Parts Actuator Calibration Stand Pistonphone Calibration Stand Calibration System Switch Box Electrostatic actuator , , 18 Adapter for microphone and preamplifier Adapter for 18 microphone and preamplifier Special gripping tools for , , and 18 microphones Cable pack for 90CA System Reference Pressure Microphone System Controller The system controller can be either PXI-based or PCI-based. It is delivered with cards and software preinstalled. Calibration system software for 90CA PXI-based version with boards for mounting in an NI PXI Express chassis or PCI-based version with boards for use in a PC
Mains Voltage
110 240VAC
Standards
IEC Standard 61094 ANSI S1.10 1966 (R1976) IEC Standard 60942 TEDS Standard IEEE 1451.4
System Integration
Before leaving the factory, the calibration system has been integrated and tested by G.R.A.S.; the individual test certificate is included.
G.R.A.S. Sound & Vibration continually strives to improve the quality of our products for our customers; therefore, the specifications and accessories are subject to change. Page 4
