Patent ID: 6034522
Filing Date: 2000-03-07
Classification: G01R

Abstract:
A transducer which comprises: a first light path which is defined by a light transmitting element, a second light path which is defined by an optical fibre, the optical fibre defining the second light path having a length which is significantly greater than that of the light transmitting element which defines the first light path, a light source arranged to direct light simultaneously into both the first and the second light paths, means for cyclically modulating the light from the source between upper and lower levels, means for detecting for light exiting from the two light paths during successive time periods that include a first time interval in which light exits from the first path only and a second time interval in which light exits from the second path only, and means for referencing the level of light that exits from one of the paths with respect to the level of light that exits from the other path.