Low frequency laser fiberoptic detector apparatus for musical instruments and intrusion detection

摘要: An optical fiber is used as a transducer to convert low frequency mechanical disturbance into amplitude modulated energy. According the preferred embodiment of invention transduction occurs by means multi-path interference phenomena capable responding acoustic information ranging from less than one hundredth cycle per second several hundred thousand cycles second. This feature makes general concept applicable use in musical instruments or security sensing device. When applied instrument it would preferably include following elements series: solid state laser, multi-mode single index optic fiber, square law detector, such photodiode, an audio amplifier and speaker. apparatus same active (i.e. detector), but section further special circuitry discrimination logic. In sensor output device can be made compatible with any number existing techniques based upon power spectrum densities frequencies domain. The length cable typically longer when employed neighborhood 100 meters.