A Novel Direct Digital Frequency Synthesis with High Frequency Accuracy and Spectral Purity

This paper presents a novel direct digital frequency synthesis (DBFS) architecture based on simple trigonometric identities. In the proposed DBFS architecture the phase value is divided into two sub components. Each component is converted to sine and cosine value by the look-up table method. The final sine and cosine outputs are reconstructed by multiplying and adding sine and cosine values of sub components based on simple trigonometric identities. The proposed architecture uses no approximation calculation. Therefore, it has no approximation error. The spurious free dynamic range (SFDR) is equal to the theoretical limits. The ROM size can be reduced to half of the Sunderland architecture. The proposed architecture is suitable for FPGA implementation, and is able to realize high frequency accuracy and spectral purity, with minimal hardware overhead