A New Compression Algorithm for DDS Look-Up Table

Abstract

In DDS technology, the signal spectrum pureness and the look-up table scale restrict to each other, due to capacity limitation, large-scale look-up table for high precision sine signal generation is often impractical. In this paper, a new DDS algorithm based on compression look-up table is proposed. First, analysis is given between the relationship of signal SNR and the look-up table scale. Second, an efficient compression look-up table is constructed, together with the relationship between look-up table scale and compression ratio. Finally, the implementation of the algorithm is presented, and the signal SNR and the compression ratio are confirmed through simulation, in which the parameters are comfortable for most DAC chips currently. For a signal with 20bits word-width, the compression ratio will be 105 approximately, while with little performance deterioration.