| 摘要 |
<p>An optical vibration analyser in which a fibre optic probe (10, 11) collects back scattered light from a non-coherent light source (15, 20) illuminating a vibrating surface (28). The vibrating surface (28) causes near parallel light close to the probe to be scattered into the end face of the probe in proportion to its amplitude. The intensity variation is detected by a planar diffused photo-diode (16, 21) and amplified to a usable level.</p><p>The amplitude of the back scattered light is very small in comparison with ambient light and other non-correlated noise from which it is extracted. The vibrations in the observed surface are excited by a sweep oscillator (2) and the received signal is processed by a dual tracking filter (6) locked to the sweep oscillator (2). The filtered output shows the mechanical position of the surface and vibration amplitude and can be directly monitored.</p> |
