| 摘要 |
Apparatus for measuring preferably the rotational speed of rotating bodies and comprising a sectored disc (3) with transparent and non-transparent sectors placed on the apparatus, a light source (4) placed on one side of the sectored disc and a sensor (5) placed in the light beam transmitted through the disc and means for transforming output signals from the sensor into information signals relating to the speed and/or acceleration of the rotating body. In order to enable the apparatus to measure speed in an interval around zero using only one stationary light source (4) and a corresponding stationary sensor (5), the light source comprises a number of separate light emitters (6) adapted to emit light pulses of displaced phase, and the sensor comprises a field of sensitivity corresponding to the width of one transparent and one non-transparent sector. |
