A device and method for measuring acoustic characteristics based on semiconductor laser external cavity

Abstract

The invention relates to the field of laser measurement, and discloses a method for measuring acoustic characteristics based on a semiconductor laser external cavity. The device includes a grating external cavity feedback semiconductor laser, a polarization spectrum generating device, a frequency stabilization feedback loop, a signal generator, a sound generator, Mixer, filter and signal collector, the signal generator is used to generate a sine wave with continuous frequency scanning to drive the sound generator to generate sound excitation, and the output signal of the grating external cavity feedback semiconductor laser is generated by the polarization spectrum generating device. It is divided into three paths, one path is fed into the frequency stabilization feedback loop and then fed back to the semiconductor laser to be tested, and the other path is injected into the mixer together with the output signal of the signal generator, and then output to the signal collector for collection after being low-pass filtered by the filter. The invention can realize the sound insulation characteristics of sound insulation systems with different structures and materials. It is of great significance to study sound sensing and acoustic precision measurement based on laser technology.

Description

technical field [0001] The invention belongs to the field of acoustic measurement, in particular to an acoustic characteristic measurement device and method based on a semiconductor laser external cavity, which is used for measuring the acoustic response characteristics of different materials or different structural systems. Background technique [0002] Traditional sound measurement methods usually use reverberation, sound insulation, anechoic box and other schemes. When measuring the sound insulation effect of materials, it is necessary to use a sound pressure meter or a sound intensity meter to directly measure the sound pressure level of the sound signal before and after passing through the material. The principle It is to use a microphone to convert the sound signal into an electrical signal, process it through a filter or an amplifier, and finally convert it into physical quantities such as sound pressure and sound intensity that represent the sound intensity, and compa...

AI Technical Summary

Problems solved by technology

[0005] The present invention can overcome the problem of insufficient low-frequency sensitivity existing in the prior art, and provides a device and method for measuring acoustic characteristics based on the external cavity of a semiconductor laser. By recording the frequency drift of the laser output frequency under sound disturbance, the sound signal or sound The induced response is converted into the fluctuation of the laser frequency in the optical frequency band relative to the reference frequency that can be measured accurately. The difference in the output frequency of the laser is used to characterize the sound insulation characteristics of different materials and different structures, and the measurement of acoustic characteristics in a wider frequency band is realized.

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