Patent ID: 7196643

Claim:
A resolver arrangement for detecting the rotational position of a rotor with respect to a stator, wherein the rotor carries a rotor coil and the stator has a pair of stator coils mutually shifted by 90°, and a carrier signal is applied to the rotor coil, the arrangement comprising a carrier signal generator and two processing channels each of which has an analog input connected a different one of the stator coils and a channel output; each of said processing channels comprising: a sigma-delta modulator with an output that supplies a bit-stream representative of an analog input signal received from a respective stator coil; a first digital filter that receives the bit-stream from the sigma-delta modulator and converts the bit-stream to intermediate digital data-words; a digital synchronous demodulator that demodulates the intermediate digital data-words in synchronism with the carrier signal providing demodulated data-words; and a second digital filter that averages the demodulated data-words and supplies digital output data-words on said channel output, the carrier signal being suppressed in said output data-words.