Low noise emission is increasingly important for all kinds of machines, equipment and consumer products, with quiet products are often preferred over more noisy ones. It therefore becomes increasingly important to measure close to the threshold of human hearing are needed.
A standard ½” microphone with high sensitivity (50 mV) has a noise floor about 16 dB(A), and the useful measurement range therefore begins at about 19 dB(A). To measure below this level, a special low-noise system is needed.
The 47HC is a prepolarized low-noise microphone set which builds on GRAS' 20+ years' of experience with state of the art low-noise measurement microphone systems. With this set, the performance previously reserved for externally polarized setups is now available for CCP (constant current powered) systems.
There are huge potential economic and environmental gains to be made from applications and tools produced using Earth observation satellite data. At this exciting time in the development of the NZ Space sector, this colloquium will:
Below 10 kHz, the standardized ear simulator does a good job at this. However, above 10 kHz its performance starts rapidly to deteriorate. The primary reason for this is its high Q resonance at 13.5 kHz.
The new GRAS High Resolution Ear Simulator mitigates this limitation. The steep resonance at 13.5 kHz has been replaced by a much dampened resonance and the useful frequency range is now extended to 20 kHz within a narrow tolerance band.
It complies with IEC60318-4 and its acoustic transfer impedance is within the tolerance band specified by IEC60318-4. From 10 to 20 kHz the transfer impedance is within ± 2.2 dB, resulting in much improved repeatability.
ETMC Technologies is proud to be exhibiting at RotorTech 2018 on the Sunshine Coast, Australia. This Meeting will be held at the The Novotel Twin Waters Resort (270 Ocean Dr, Twin Waters QLD 4564, Australia) on the 24th through 26th May 2018.
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