Acoustics and Vibration


The Acoustics & Vibration Laboratory develops, maintains and disseminates acoustics, ultrasound and vibration related national measurement standards in Singapore. They include airborne acoustics (20 Hz to 20 kHz), medical ultrasound power (100 mW to 1 W) and vibration (0.1 Hz to 350 kHz). Beyond measurement traceability dissemination, these measurement standards open up opportunities for local and overseas sensing instrument developers and manufacturers to understand their device performance through comprehensive characterization. We also carry out R&D for industry and other stakeholders to develop and apply acoustics and vibration measurement techniques for various applications.

Acoustics Standards

Sound pressure level (decibel [dB]) is realised using laboratory microphones in a reciprocity calibration arrangement, according to the international standard IEC 61094-2.

Services are provided for:
  • Calibration of Laboratory Standard (LSP) Microphones based on IEC 61094-2 Standard.
  • Calibration of measuring microphones based on IEC 61094-6 Standard.
  • Calibration of acoustic calibrators and pistonphones based on IEC 60942 Standard.
  • Calibration of sound level meters and sound measuring instruments based on IEC 61672-3 Standard.
  • Calibration of Octave-band Filters based on IEC 61260 Standard.


Microphone calibration system


Sound level meters


Sound calibrators

Ultrasound Standards

Ultrasound output power measurement system is realised by Radiation Force Balance (RFB) method according to IEC 61161 in the measurement range of 1 MHz to 10 MHz and 10 mW to 1 W. It is used to measure the output power level of medical ultrasound transducers.


Vibration Standards

The primary vibration standard is realised according to ISO 16063-11, using laser interferometry as an absolute reference. Standard Reference Accelerometers are calibrated against the primary standard. NMC is able to calibrate vibration transducers in the frequency range from 0.1 Hz to 350 kHz.

Services are provided for:

  • Calibration of vibration measuring instruments.
  • Determination of charge sensitivities for signal conditioners.
  • Determination of voltage gain sensitivities for power supply couplers.
  • Measurement of output acceleration of calibration exciters.

Primary & secondary calibration of vibration sensors


Vibration sensors


Vibration monitoring


Vibration measuring instrument

Underwater Hydrophone Standard

The underwater hydrophone calibration standard is realised based on Section 14 of IEC 60565:2006 using a vibrating water column. The hydrophone calibration is done through comparison with a reference hydrophone where both units are subjected to the same hydrodynamic pressure field in the water column.

Services provided are:

  • Underwater calibration of hydrophones in the frequency range from 30 Hz to 2000 Hz.

  • Airborne calibration of hydrophones at the frequency of 250 Hz for selected models.

 

Typical Hydrophones