Direct digital frequency synthesizers of high spectral purity based on quadratic approximation

Author

Nittylahti, J.

Volume

3

fYear

2002

fDate

2002

Firstpage

1095

Abstract

In this paper, we analyze the design and the possible optimization methods of the direct digital frequency synthesizer (DDFS) based on quadratic approximation. The goal is to design a DDFS with reduced hardware cost and very high spectral purity. For the DDFS based on quadratic approximation, there is a trade-off between the size of the memory and the approximation logic. We show that by exploring this trade-off, it is possible to design a DDFS which requires less hardware and features higher spectral purity than the previously presented solutions. By using the proposed design method, a DDFS that generates 16-bit sinusoidal waves with a spurious free dynamic range of 132 dBc (126 dBc if the phase is truncated) was designed.

Keywords

circuit optimisation; direct digital synthesis; function approximation; network synthesis; 16 bit; DDFS design; approximation logic; direct digital frequency synthesizers; hardware cost; memory size; optimization methods; quadratic approximation; sinusoidal waves; spectral purity; spurious free dynamic range; truncated phase; Approximation algorithms; Approximation error; Costs; Design methodology; Dynamic range; Frequency synthesizers; Hardware; Logic; Polynomials; Table lookup;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronics, Circuits and Systems, 2002. 9th International Conference on

Print_ISBN

0-7803-7596-3

Type

conf

DOI

10.1109/ICECS.2002.1046442

Filename

1046442