基于半导体激光器的自混合干涉效应，通过实验研究了扬声器的振动特性。实验中，用粘在扬声器振膜上的反射镜作为目标物体（该反射镜的反射率为95％，扬声器用50Hz的正弦波驱动）,然后通过条纹计数法获得扬声器的振幅。实验结果表明，在一定范围内，扬声器的振幅与驱动电压呈线性关系。该实验装置极其简单紧凑，自混合干涉信号也十分清晰，实验方法迅速，价格低廉，易实现，而且不需要专用电源，也不需要其他的光学仪器，这一系列优点充分表明自混合干涉技术在振动测量领域具有广阔的发展前景。

The vibration characteristic of loudspeakers is investigated experimentally, based on the self-mixing interference effect of semiconductor laser diode. As a target, a reflector with reflectivity of 95% is mounted on the loudspeaker, which is driven by a sine signal at 50Hz frequency, and a self-mixing interference signal is obtained with an extremely simple optical setup. Then the vibration amplitude of loudspeaker is figured out through the interference fringe counting method. The results show that the vibration amplitude, which responses to the driving voltage, exhibits good linearity in corresponding range. It is a fast, low-cost and easy to perform method that does not require special driving device or other optical apparatus. This experiment illustrates the effectiveness of the self-mixing technique in the field of vibration measurements.