GRAS 40HH 1/2'' 低噪音传声器系统

Freq range: 10 Hz to 16 kHz
Dyn range: 6.5 dB(A) to 113 dB
Sensitivity: 800 mV/Pa

GRAS 40HH 1/2" 低噪声传声器系统可以测量接近人类听觉阈值的声压级；即使是非常安静的产品，也非常适合用于声功率测量。它的动态范围非常宽，可测量 20 μPa 时低至 6.5 dB（1/3 倍频程频带）的 20 Hz 至 20 kHz 的声压级。

Technology

Typical applications and use

Very Low Sound pressure measurements
Low noise product measurements
Sound power measurements at low sound pressure levels
Measurements on hard-disk drives, computerproducts, quiet rooms etc.

The 40HH comprises:

a special high-sensitive 1/2" GRAS 40AH Condenser Microphone
a special 1/2" GRAS 26HH Lownoise Preamplifier

The preamplifier and microphone are an individually matched combination. To complete the system, a special single or 10-channel power module is required and is available, i.e. GRAS 12HF for single-channel measurements or GRAS 12HM for multi-channel measurements.

The chosen power module provides all necessary voltages for powering the preamplifier(s) as well as polarizing the microphone(s).

Preamplifier

The GRAS 26HH Preamplifier has a built-in overload indicator (which is repeated on the chosen power supply) and a frequency correction facility for both pressure-microphone operation as well as free field microphone operation.

Microphone

The GRAS 40AH Microphone is an externally polarized microphone with a specially reduced inherent noise floor in order to achieve a high dynamic range and wide frequency range. Its diaphragm is specially tuned to yield high sensitivity coupled with low internal-noise generation.

Frequency Response and Noise Floor

The chosen power supply has a two-position switch for selecting which microphone operation to use, i.e.pressure or free-field. A typical free-field response for an angle of incidence of 0° is shown in the data sheet when GRAS 40HH is switched to free-field operation. Also shown is a complete low-noise measuring system, a typical noise floor in 1/3-octave bands for both the linear and A-weighted cases.

Specifications

Frequency range (±1 dB)

12.5 to 10k

Frequency range (±2 dB)

10 to 16k

Frequency range (±3 dB)

6 to 20k

Dynamic range lower limit (microphone thermal noise)

dB(A)

6.5

Dynamic range upper limit

113

Set sensitivity @ 250 Hz (±2 dB)

mV/Pa

800

Polarization voltage

200 V / Traditional

Microphone venting

Rear

Output impedance

Temperature range, operation

°C / °F

–20 to 60 / -4 to 140

Temperature range, storage

°C / °F

-40 to 85 / -40 to 185

CE/RoHS compliant/WEEE registered

Yes/Yes/Yes

Typical frequency response

Typical noise floor shown in 1/3-octave bands - linear and A-weighted cases

GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.

Ordering info

Included items

GRAS 40AH	High sensitive 1/2" microphone
GRAS 26HH	Lownoise 1/2" preamplifier

Optional items

GRAS 12HF	1-Channel Power Module for Lownoise Systems
GRAS 12HM	10-Channel Power Module for Lownoise Systems
GRAS AM0363	Windscreen for 1" Microphones
GRAS 42AA	Pistonphone, Class 1
GRAS RA0090	Pistonphone Coupler
GRAS AL0006	Tripod
GRAS RA0093	Adjustable, high quality, stainless steel tripod adapter
GRAS RA0095	Dehumidifier for 1” microphones
GRAS AA0046	3 m LEMO 7-pin - LEMO 7-pin Cable for Low-noise measuring system
GRAS AA0047	10 m LEMO 7-pin - LEMO 7-pin Cable for Low-noise measuring system