An efficient direct digital frequency synthesizer based on two-level table lookup
Jen-Chuan Chih, J.-J. Chou, Sau-Gee Chen · 2002
This paper proposes a new direct digital frequency synthesizer (DDFS). It has the merits of high speed, low complexity and high spectrum purity. It is based on the Taylor's expansion method for sinusoidal and cosine functions, combined with, a two-level table-lookup algorithm. The new DDFS is efficient, with a small table size and low computational complexity. In all, this new DDFS needs three lookup tables, each of size 2/sup N/4/, which is smaller than the other table-lookup methods, such as Madisetti, et al. (1999), (of size 2/sup N/3/). The DDFS is non-recursive, which is free of error-propagation problem inherently in the recursive DDFSs. For 11-16-bits example, simulation shows that the new DDFS has a high SFDR (spurious free dynamic range) of 100 dBc.