If the speed measurement of resolver and the generation of PWM signals are implemented with single microcontroller, it is easy to reduce the system cost and to avoid the switching noise of inverters. To avoid the switching noise and to improve the accuracy of measurement, PWM switching and A/D sampling of the resolver should be synchronized. Phase angle of the resolver excitation signal is increased in stepwise manner, then, the output signal of the resolver is measured in each step. From the measured data, the optimal phase angle of resolver excitation signal is estimated using the least square approximation method.