EURASIP Journal on Embedded Systems 
Volume 2008 (2008), Article ID 242584, 12 pages
doi:10.1155/2008/242584
Research Article

Accuracy Constraint Determination in Fixed-Point System Design

D. Menard,1 R. Serizel,2 R. Rocher,1 and O. Sentieys1

 1IRISA/INRIA, University of Rennes, 6 Rue de Kerampont, 22300 Lannion, France
2K.U.Leuven, ESAT/SISTA, Kasteelpark Arenberg 10, 3001 Leuven-Heverlee, Belgium
Received 12 March 2008; Revised 4 July 2008; Accepted 2 September 2008

Recommended by Markus Rupp

Abstract

Most of digital signal processing applications are specified and designed with floatingpoint arithmetic but are finally implemented using fixed-point architectures. Thus, the design flow requires a floating-point to fixed-point conversion stage which optimizes the implementation cost under execution time and accuracy constraints. This accuracy constraint is linked to the application performances and the determination of this constraint is one of the key issues of the conversion process. In this paper, a method is proposed to determine the accuracy constraint from the application performance. The fixed-point system is modeled with an infinite precision version of the system and a single noise source located at the system output. Then, an iterative approach for optimizing the fixed-point specification under the application performance constraint is defined and detailed. Finally the efficiency of our approach is demonstrated by experiments on an MP3 encoder.