Patent ID: 6894629

Claim:
A resolver/digital (R/D) converter configured to find an angle of a rotor axis of a resolver, said R/D converter comprising: a first converter configured to convert a sine wave output and a cosine wave output of said resolver into a digitized sine wave output and a digitized cosine wave output respectively; an angle data memory configured to store angle data in the range of 0° to 90° in advance; an address converter configured to convert one of the digitized sine wave output and the digitized cosine wave output to an address associated with the angle data memory; an angle data reader configured to provide the address to said angle data memory, and read the angle data located in said angle data memory at the provided address; a discriminator configured to determine to which one of four quadrants formed by dividing the angle space of said resolver into four, said rotor axis belongs, based on a polarity of the digitized sine wave output and the digitized cosine wave output from said A/D converter; and a calculator configured to find a final angle of the rotor axis of said resolver by combining an offset value associated with the angle of the rotor axis, the offset value based on the determined one of the four quadrants, and the angle data read by said angle data reader.