A DEVICE AND A METHOD FOR NON-CONTACTUAL SPEED MEASUREMENT ON SURFACES

摘要

The invention relates to a device for contactlessly measuring the speed of a n object (10) moving over a surface (12). The device comprises a device (20) f or emitting a signal with a fixed frequency onto the surface (12) at an angle (.alpha.) in or towards the direction of movement, said angle (.alpha.) bein g altered by the movement of the object (10), and for receiving a Doppler displaced signal reflected by the surface (12). The invention also provides a device (24) for combining a plurality of reflected Doppler displaced signals that are received one after the other in order to produce a combined spectru m (50; 60, 62, 64). The device for contactlessly measuring speed also comprise s a device (24) for determining the spectral proportion from the combined spectrum with the highest or lowest frequency, exceeding a predetermined signal, and a device (30) for deriving the speed from the frequency of the determined proportion of the spectrum.