Patent ID: 8087304

Claim:
A method for reducing the noise in a signal from a torque sensor caused by near magnetic field sources, the method comprising the steps of: providing a torque sensor comprising: a longitudinally extending member; a magnetoelastically active region directly or indirectly attached to/or forming a part of the surface of the member, the active region comprising at least one region magnetized in a first substantially circumferential direction in such a manner that torque applied to the member is proportionally transmitted to the active region; at least one primary magnetic field sensors arranged proximate the at least one region for outputting a first signal corresponding to a torque-dependent magnetic flux emanating from the active region; at least one secondary magnetic field sensor axially spaced in a first direction by a pre-determined first distance from the plurality of primary magnetic field sensors for outputting a second signal corresponding to an ambient magnetic flux emanating from the near magnetic field source; at least one secondary magnetic field sensor axially spaced in a second direction opposite the first direction a pre-determined second distance from the plurality of primary magnetic field sensors for outputting a third signal corresponding to the ambient magnetic flux emanating from the near magnetic field source; receiving the first signal upon the application of the torque; receiving the second and third signals; and adjusting the first signal using the second and third signals thereby compensating for the effects of the near magnetic field source.