A novel method for estimating the angle from analog co-sinusoidal quadrature signals

The paper presents a new low cost and accurate method for determining the angle from sine and cosine signals produced by resolvers and sinusoidal encoders. In the proposed scheme, multiple phase-shifted sinusoids (PSS) are derived from these signals. The pseudo-linear segments of the PSS, alternating around zero crossings, are used to determine the angle continuously and linearly without the need for processors or look-up tables. The new converter implemented with eight PSS is described in details; this scheme is characterized by a theoretical absolute error of 0.028° within the 360° range. The converter was built using basic analog components. Experimental results generated with a revolver showed excellent agreement with theory and simulation.