Hệ thống micro giảm tiếng ồn GRAS 40HH 1/2''

GRAS 40HH 1/2" Lownoise Microphone System

Part Number: GRAS 40HH

Category: GRAS Sound & Vibration

Status: Available

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

Sale Price: Liên hệ

0903368648

+84903368648

The GRAS 40HH 1/2" Lownoise Microphone System can measure sound pressure levels down to close to the threshold of human hearing; and is amply suitable for use in sound-power measurements on even very quiet products. Its very wide dynamic range permits measurements down to 6.5 dB re. 20 μPa (in 1/3-octave bands) from 20 Hz to 20 kHz.

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)	Hz	12.5 to 10k
Frequency range (±2 dB)	Hz	10 to 16k
Frequency range (±3 dB)	Hz	6 to 20k
Dynamic range lower limit (microphone thermal noise)	dB(A)	6.5
Dynamic range upper limit	dB	113
Set sensitivity @ 250 Hz (±2 dB)	mV/Pa	800
Polarization voltage		200 V / Traditional
Microphone venting		Rear
Output impedance	Ω	47
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