Patent ID: 6885310

Claim:
A phase difference detection device for detecting a phase difference between first and second A.C. signals based on output signals from a position detector, said phase difference having a value corresponding to a position-to-be-detected, said phase difference detection device comprising: a first circuit that performs an operation between said first and second A.C. signals so as to synthesize a first data signal having an electric phase angle shifted in one of positive and negative directions in correspondence to the position-to-be-detected; a second circuit that performs an operation between said first and second A.C. signals so as to synthesize a second data signal having an electric phase angle shifted in other of positive and negative directions in correspondence to the position-to-be-detected; a first operation circuit operatively coupled to said first circuit to measure an electric phase difference between said predetermined reference signal and said first data signal to obtain first phase data; a second operation circuit operatively coupled to said second circuit to measure an electric phase difference between said predetermined reference signal and said second data signal to obtain second phase data; and a third operation circuit operatively coupled to said first and second operation circuit to calculate position detection data corresponding to the position-to-be-detected on the basis of said first and second phase data.