THE LARYNGOSTROBOSCOPE
L. S. POWELL · Archives of Otolaryngology - Head and Neck Surgery · 1934
The stroboscopic principle was first used for the examination of the vibrations of a taut string making a musical note. As these vibrations are too rapid for visual perception it was necessary to find some means whereby a slow motion effect could be obtained. This was done by the use of interrupted light, usually with a rapidly revolving perforated disk. By this means a fleeting glimpse was obtained as each perforation in the disk came into view. This divided the cycles or phases of the vibrations in such a way that there was an apparent retarding of the movement, although a true picture was given in its complete cycle. In other words, a small bit of each phase is seen, which, coupled with the next succeeding glimpse in a later cycle, gradually builds up an apparently complete cycle or vibration from many actual vibrations. The human vocal cords also vibrate