Title :
An efficient direct digital frequency synthesizer based on two-level table lookup
Author :
Chih, Jen-Chuan ; Chou, Jun-Yei ; Chen, Sau-Gee
Author_Institution :
Nat. Chiao Tung Univ., Hsinchu, Taiwan
fDate :
6/23/1905 12:00:00 AM
Abstract :
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 2N/4, which is smaller than the other table-lookup methods, such as Madisetti, et al. (1999), (of size 2N/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
Keywords :
computational complexity; direct digital synthesis; pipeline arithmetic; polynomial approximation; table lookup; Chebyshev approximation; Taylor´s expansion method; VLSI implementation; cosine functions; direct digital frequency synthesizer; high spectrum purity; high speed; low complexity; low computational complexity; nonrecursive polynomial-based DDFS; sinusoidal functions; small table size; spurious free dynamic range; two-level table-lookup algorithm; Approximation algorithms; Band pass filters; Chebyshev approximation; Computational complexity; Digital-analog conversion; Dynamic range; Frequency synthesizers; Low pass filters; Polynomials; Table lookup;
Conference_Titel :
Frequency Control Symposium and PDA Exhibition, 2001. Proceedings of the 2001 IEEE International
Conference_Location :
Seattle, WA
Print_ISBN :
0-7803-7028-7
DOI :
10.1109/FREQ.2001.956389
