60MHz direct digital frequency synthesizer SSB phase noise

The phase noise and spurious spectrum are the key characters in direct digital frequency synthesizer (DDS) applied in radar and communications. The phase noise generated by phase truncation is analyzed in this paper. And phase noise generated by the size of ROM look-up table and the performance of DAC is also investigated. Meanwhile the methods designing about 60MHz, in 5Hz step, direct digital frequency synthesizer (DDS) is introduced in this paper. On the basis of test results, the distribution characteristics of output phase noise are analyzed.