| 摘要 |
Compensation is provided for changes in the stored magnetisation of a magnetic-based transducer having a transducer region (12) of permanent magnetisation which emanates a magnetic field that is a function of an applied stress such as torque or a bending force. Magnetic field sensors (MFS1-4) are employed to derive a stress-dependent signal (MFS1,2) and a reference signal (MFS3,4) that is independent of the applied stress. The reference signal is obtained by detecting the emanated field at a point where it is substantially unaffected by torque, preferably by a differential measurement of two sensors (Fig. 4), or at two axially-spaced points at which detection is torque-dependent in a substantially equal manner (Fig. 10b).
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