Patent attributes
A signal processing unit includes an integrating unit. The integrating unit is composed of a plurality of digital elements and is operative to integrate a detection signal over every quarter of one cycle of the detection signal to generate an integration value. The integration values to be generated are represented as S1, S2, S3, and S4. A calculating unit includes a plurality of digital elements and performs addition and subtraction on the generated integration values in accordance with the following equations used to calculate an in-phase component and a quadrature-phase component of (Ip=S4p−3+S4p−2−S4p−1−S4p) and (Qp=S4.4−S4p−−S4p−1+S4p). Where Ip represents the in-phase component and Qp represents the quadrature-phase component. An amplitude obtaining unit obtains an amplitude of the detection signal based on the in-phase component and the quadrature-phase component.
