Speaker
Description
Infrasound can be detected in nature and human activities, such as earthquakes, volcanic eruptions, mudslides, supersonic flight, etc. The monitoring of infrasound sound pressure signal mainly depends on the infrasound sensor, and the accurate measurement of infrasound sound pressure mainly depends on the calibration of the infrasound sensor.
Since the NPL developed laser-pistonphone to calibrate microphone, laser pistonphone became a feasible device in infrasound calibration. In this paper, a infrasound laser pistonphone was developed down to 0.001Hz, including an infrasound sound pressure generator, feedback control and infrasound excitation system, data acquisition conditioning system and ultra-low frequency laser interferometer.
Furthermore the external environmental noise will interfere with the atmospheric pressure in the cavity of the infrasound generator, which will affect the waveform generated by the infrasound generator and produce interference and waveform distortion. A differential noise reduction system was used in this device in order to obtain infrasound time-domain waveform from 0.001Hz to 20Hz with lower fluctuation.
A Mb3a infrasound sensor was calibrated by this device from 0.01Hz to 31.5Hz, and the result fit the company calibration data very well.
| [email protected] |
