Patent ID: 7401001

Claim:
A position determining system for determining a position of a rotor of a rotating motor, said system comprising: sensing means coupled to the rotor for generating in response to a rotation of the rotor a quadrature signal comprising a sine component and a cosine component, and calculating means for calculating a sum (A 2 ) of a squared value of the sine component (A 2 sin 2 x) and a squared value of the cosine component (A 2 cos 2 x), an amplitude correction factor (A) as a squared root of the sum (A 2 ), an amplitude corrected sine component (sin(x)) as the sine component (Asin(x)) divided by the amplitude correction factor (A) and an amplitude corrected cosine component (cos(x)) as the cosine component (Acos(x)) divided by the amplitude correction factor (A), weighting an inverse sine value of the amplitude corrected sine component (sin(x)) with a weighting factor for favoring the inverse sine value around its zero crossings to obtain a weighted sine value, weighting an inverse cosine value of the amplitude corrected cosine component (cos(x)) with a weighting factor for favoring the inverse cosine value around its zero crossings, to obtain a weighted cosine value, and an output sum of the weighted inverse sine value of the amplitude corrected sine component (sin(x)) and the weighted inverse cosine value of the amplitude corrected cosine component (cos(x)), and output means for outputting the output sum for determining the position of the rotor.