A Low-Spurious Direct Digital Frequency Synthesis Based on FPGA
Yang Jian · Dianzi qijian · 2011
After analyzing the principle of DDS,the causes for its spur and some methods to reduce spurs,a new and effective method of spur-reducing was proposed.Using the trigonometric transformation,the low B-bits which were usually be truncated in the output of phase accumulator were utilized.The results in Simulink appeared that the spurious performance of the optimized DDS was improved to 60 dB,when the phase accumulator is 32 bit and 12 bit wide for look-up table addressing.The DDS was implemented in the FPGA by using the Verilog language as a design input,and finally an ideal sine wave was observed by oscilloscope.