digital output angle u03b8 u2032 through an angle calculation loop formed by the components listed above and outputs the digital output angle u03b8 u2032 the digital output angle u03b8 u2032 is input to the sin rom 26 and the sin rom 26 produces a sin u03b8 u2032 which is a sine value of the digital output angle u03b8 u2032 and outputs the sin u03b8 u2032 to the multiplier 21 similarly the cos rom 27 produces a cos u03b8 u2032 which is a cosine value of the digital output angle u03b8 u2032 and outputs the cos u03b8 u2032 to the multiplier 22 the multiplier 21 multiplies the resolver signal s 1 by sin u03b8 u2032 and outputs the product to the subtractor 23 the multiplier 22 multiplies the resolver signal s 2 by cos u03b8 u2032 and outputs the product to the subtractor 23 the subtractor 23 subtracts the output of the multiplier 21 from the output of the multiplier 22 and outputs the difference to the synchronous detecting circuit 24 the signal input from the subtractor 23 to the synchronous detecting circuit 24 is expressed as follows the synchronous detecting circuit 24 synchronously detects this signal with reference to the excitation signal sin u03c9t input from the excitation signal generator 30 and eliminates sin u03c9t from the signal to output a deviation sin u03b8 u2212 u03b8 u2032 as a detection output to the controller 25 the controller 25 adjusts the digital output angle u03b8 u2032 to make the deviation sin u03b8 u2212 u03b8 u2032 equal to 0 as a result u03b8 equals to u03b8 u2032 and the.