Abstract:
Because of DDS's inherent digital characteristic,there are many spuriousness presences in its output.In general,the spuriousness restraining is implemented by low-pass or band-pass filter,but the result is always not ideal.For the PLL has better performances in narrowband filtering and frequency tracking,the paper presents a new method which based on PLL accomplish the spuriousness restrained.In the end,using dspbuilder toolbox of Altera corp.we verify the validity of the method by simulation.