US Patent 7401001 Position determining

A position determining system for determining a position of a rotor of a rotating motor has sensors that are coupled to the rotor. The sensors generate, in response to a rotation of the rotor, a quadrature signal that has sine and cosine components. The position determining system calculates a sum (A2) of a squared value of the sine component (A2sin2x) and a squared value of the cosine component (A2cos2x). An amplitude correction factor (A) is calculated as the squared root of the sum (A2). An amplitude corrected sine component (sin(x)) is obtained by dividing the sine component (Asin(x)) by the amplitude correction factor (A). An amplitude corrected cosine component (cos(x)) is obtained by dividing the cosine component (Acos(x)) by the amplitude correction factor (A).