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Research on improved CORDIC algorithm for high accuracy DDS signal source

The Direct Digital Synthesis (DDS) signal source that adopts ROM look-up table has serious signal spurious and deterioration of spectral properties, so it can't meet the requirements of Nuclear Magnetic Resonance Gyroscope (NMRG). For the problem, on the basis of basic principle analysis of Coordinate Rotation Digital Computer (CORDIC) algorithm, a new improved algorithm is proposed, which combines the scaling-free architecture and the conventional architecture, and through the error analysis, upper bound of the errors can reach at 13th deci mal bit position. Then, a design of novel DDS signal source based on the improved CORDIC algorithm is realized on Field Programmable Gate Array (FPGA). Experimental results show that the signal accuracy of the DDS based on the improved CORDIC can reach 10−5 order of magnitude and spectrum spur is small. The improved algorithm has advantages in speed, accuracy and low consumption, which are significant in developing high accuracy DDS signal source.