扬声器锥体振动的测量及可视化(待续)

Measurement and Visualization of Loudspeaker Cone Vibration(Continued)

利用激光三角测量原理的技术可以实现对扬声器锥体振动的光学测量(扫描振动测量法),这项技术与多谱勒干涉测量法相比更为经济高效。三角测量原理的传感器主要得到的是位移数据,因此,要测量最高可达20 kHz时的振动盆的分裂振动模式,就需要进行足够高信噪比的高级信号处理。除了可以提供辐射图形的闪频动画显示,也将提出新的针对测量数据实现可视化的分解技术。可以把总的振动分解成径向模态的振动与周向模态的振动;也可以分解成辐射振动分量和非辐射振动分量。这种后处理方法揭示出了扬声器锥体极其重要的振动模式,也简化了对于声辐射(振动)的解读,并给出了进一步改善的方向。

Optical measurement of loudspeaker cone vibration （scanning vibrometry） can also be accomplished by using Laser triangulation technique which is a cost effective alternative to Doppler interferometry. Since triangulation sensors provide primarily displacement advanced signal processing is required to measure the break - up modes up to 20 kHz at sufficient signal to noise ratio. In addition to stroboscopic animation of the radiation pattern a new decomposition technique is presented for the visualization of the measured data. Radial and circular modes can be separated and the total vibration can be split into radiating and non - radiating vibration components. This kind of post - processing reveals critical vibration modes, simplifies the interpretation and gives indications for further improvements.