Title :
Direct digital frequency synthesizers of high spectral purity based on quadratic approximation
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;
Conference_Titel :
Electronics, Circuits and Systems, 2002. 9th International Conference on
Print_ISBN :
0-7803-7596-3
DOI :
10.1109/ICECS.2002.1046442
