Abstract: Disclosed is a microcontroller based Resolver-to-Digital converter in which synchronous sample-and-hold type demodulation is used with an optimum time of the sample-and-hold established by control of the phase and the magnitude of the reference voltage supplied to the resolver as a function of the resolver's electrical characteristics, thus minimizing the quadrature and the even harmonics effects which are a byproduct of the resolver. The demodulated resolver outputs are filtered and are converted to digital form with the use of an A/D converter integral or external to the microcontroller. The magnitude of the reference voltage is set to an optimum value in order to utilize the full range of the A/D converter. Using digital signal processing techniques and known trigonometric identities the shaft angle of the resolver is extracted from the A/D outputs and supplied to the output latches in continuous or bus controlled fashion.