Patent ID: 8058833

Claim:
A method of generating a motor control signal for a motor having a rotor that rotates at a rotational rate, the method comprising the steps of: generating first, second, and third sinusoidal signals, each sinusoidal signal being 120-degrees out of phase with the other sinusoidal signals; differentiating the first, second, and third sinusoidal signals to obtain first, second, and third cosine signals, respectively; subtracting the first sinusoidal signal from the third sinusoidal signal to obtain a first sinusoidal difference signal; subtracting the second sinusoidal signal from the first sinusoidal signal to obtain a second sinusoidal difference signal; subtracting the third sinusoidal signal from the second sinusoidal signal to obtain a third sinusoidal difference signal; multiplying the first sinusoidal difference signal and the second cosine signal to obtain a first product signal; multiplying the second sinusoidal difference signal and the third cosine signal to obtain a second product signal; multiplying the third sinusoidal difference signal and the first cosine signal to obtain a third product signal; summing the first, second, and third product signals to obtain a summation signal; and multiplying the summation signal by a constant to obtain a rate signal that is proportional to the rotational rate of the rotor.