SYNCHRONOUS RESOLVER/DIGITAL CONVERTER

PURPOSE:To simplify a circuit, by converting a synchronous signal to a resolver signal and selecting a quadrant at a digital angle before separately multiplying the sine and cosine based on conversion from the given digital angle to calculate difference. CONSTITUTION:A synchronous signal 1 is converted to resolver signals 11, 12 of sine and cosine systems. The resolver signals inputted to a quadrant selection part 20 are quartered in a synchronous angle 360 deg. to quadruple the resolving power of an angle deviation difference operation part 90. The digital angle from an A/D converter 30 is outputted as a digital angle phi by an angle operation part 41 and inputted to the quadrant selection part 20 and a sine/ cosine converting part 42. The converting part 42 generates SINphib and COSphib which are, in turn, inputted to multiplying type D/A converters 92a, 92b along with the resolver signals 21, 22 from the quadrant selection part 20 to be converted and subtracted by a substractor circuit 90c and filtered by a band-pass filter (BPF) 65 and detected in phase on the basis of a reference signal 2 by a phase detector 50. Further, processing is performed by a low-pass filter (LPF) 60 and the A/D converter 30 to output a digital angle phi. By this method, a circuit or adjustment is simplified.