Implementation of high precision DDFS signal source based on FPGA
Gao Ji-xiang · Electronic Design Engineering · 2010
In order to design a high precision signal source and reduce the cost of the design,direct digital frequency synthesis(DDFS) technology is utilized in the low-cost FPGA Cyclone II,and sin function data is stored in ROM of FPGA with the compress rate 1/4 in this design.A high precision DDS signal source is implemented with the 50MHz outside clock frequency based on FPGA.Meanwhile,triangular signal,saw-tooth signal,square signal,plus 2-ASK,2-PSK and 2-FSK are implemented as well.The system also has the frequency sweep and wave repeat times assignment functions etc.Simulation results show that this signal source has highest frequency 9.375MHz,lowest frequency 0.034 92Hz,and frequency step 0.034 92Hz,it also has the advantages of low manufacture cost and rich function.