Title :
Laser torquemeter: immunity to memory quantisation noise
Author :
Wilmshurst, T.H. ; Rothberg, S.J. ; Halliwell, N.A.
Author_Institution :
Dept. of Electron., Southampton Univ., UK
Abstract :
Operation of the laser torquemeter relies on the periodicity of the speckle pattern backscattered from a rotating shaft. In the previous system a minimum measurable twist of 0.7\´ was imposed by address quantisation of the stored speckle pattern signals. The arrangement described provides immunity to this quantisation and the associated limit cycle oscillation, reducing the noise spectrum level to 3"/Hz12/ RMS while allowing 100 time-resolved torque readings per rotation.
Keywords :
measurement by laser beam; speckle; torquemeters; address quantisation; immunity to memory quantisation noise; laser torquemeter; limit cycle elimination; quantisation error elimination; shaft twist measurement; speckle pattern periodicity; stored speckle pattern signals;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:19911261
