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

fYear

2001

fDate

6/23/1905 12:00:00 AM

Firstpage

824

Lastpage

827

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 2^N/4, which is smaller than the other table-lookup methods, such as Madisetti, et al. (1999), (of size 2^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

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Frequency Control Symposium and PDA Exhibition, 2001. Proceedings of the 2001 IEEE International

Conference_Location

Seattle, WA

ISSN

1075-6787

Print_ISBN

0-7803-7028-7

Type

conf

DOI

10.1109/FREQ.2001.956389

Filename

956389