Design of FPGA-based high speed synchro-to-digital converter

A new design of synchro-to-digital converter which employs XC3S400 of the Spartan-3 series FPGA is introduced to compute the shaft angle of the synchro which plays an important part in angular measurement.The output voltages are transferred into FPGA and interpreted to get the angular position information with Verilog HDL according to the measuring principle of the synchro.CORDIC algorithm which is based on angle quantization is applied to the implementation of the arctan function,and the rotation steps are modified to improve the accuracy and speed performance.The converter is tested for different angular displacements and initial positions of the shaft,and the results demonstrate that the accuracy is high with the maximum absolute error of ≤0.01°and the angle range of [-360°,360°]and all are found to be satisfactory.