Automated fixed-point data-type optimization tool for signal processing and communication systems

ABSTRACT

A tool that automates the floating-point to fixed-point conversion (FFC) process for digital signal processing systems is described. The tool automatically optimizes fixed-point data types of arithmetic operators, including overflow modes, integer word lengths, fractional word lengths, and the number systems. The approach is based on statistical modeling, hardware resource estimation and global optimization based on an initial structural system description. The basic technique exploits the fact that the fixed point realization is a weak perturbation of the floating point realization which allows the development of a system model which can be used in the optimization process.

REFERENCES

• 1: W. R. Davis, et al, "A design environment for high-throughput low-power dedicated signal processing systems," IEEE Journal of Solid State Circuits, vol. 37, No. 3, pp. 420--431, Mar. 2002.
• 2: K. Kuusilinna, et al, "Real-time System-on-Chip Emulation," Chapter 10, Winning the SoC Revolution, Kluwer Academic Publishers, pp. 229--253, 2003.
• 3: The MathWorks, Inc. Simulink. {Online}. Available: http://www.mathworks.com.
• 4: The Xilinx, Inc. System Generator. {Online}. Available: http://www.xilinx.com.
• 5: H. Keding , M. Willems , M. Coors , H. Meyr, FRIDGE: a fixed-point design and simulation environment, Proceedings of the conference on Design, automation and test in Europe, p.429-435, February 23-26, 1998, Le Palais des Congrés de Paris, France
• 6: S. Kim, K. Kum and W. Sung, "Fixed-point optimization utility for C and C++ based digital signal processing programs," IEEE Trans. Circ. Sys. II: Analog and Digital Signal Processing, vol. 45, no.11, pp1455--1464, 1998.
• 7: Stephen Boyd , Lieven Vandenberghe, Convex Optimization, Cambridge University Press, New York, NY, 2004
• 8: D. Menard, and O. Sentieys, "A methodology for evaluating the precision of fixed-point systems," Proc. IEEE Int. Conf. on Acoust., Speech, and Signal Processing, vol. 3, 2002. pp. 3152--3155.
• 9: M. A. Cantin, Y. Savaria, and P. Lavoie, "A comparison of automatic word length optimization procedures," Proc. IEEE Int. Sym. Circs. and Sys, 2002, vol. 2, pp. 612--615.
• 10: C. Shi, and R. W. Brodersen, "Floating-point to fixed-point conversion with decision-errors due to quantization," IEEE Int. Conf. on Acoust., Speech, and Signal Processing, 2004.
• 11: C. Shi, and R. W. Brodersen, "A perturbation theory on statistical quantization effects in fixed-point DSP with non-stationary inputs," IEEE Int. Sym. Circs. and Sys, 2004.
• 12: C. Shi, and R. W. Brodersen, "An automated floating-point to fixed-point conversion methodology," Proc. IEEE Int. Conf. Acoust., Speech, and Signal Processing, Vol. 2, pp. 529--532, April 2003.
• 13: M. Nemani, and F. N. Najm, "High-level area and power estimation for VLSI circuits," IEEE Tran. Computer-Aided Design of Integrated Circuits and Systems, vol 18, pp. 697--713, June 1999.
• 14: Project descriptions of Berkeley Wireless Research Center. {Online} Available: http://bwrc.eecs.berkeley.edu
• 15: C. Shi, "A tutorial on using floating-point and fixed-point our conversion tool," {Online} Available: http://bwrc.eecs.berkeley.edu/people/Grad_Students/ccshi/research/FFC/documentation.htm

INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.3 SPECIAL-PURPOSE AND APPLICATION-BASED SYSTEMS

Additional Classification:
  J. Computer Applications
  J.6 COMPUTER-AIDED ENGINEERING
      Subjects: Computer-aided design (CAD)

General Terms:
Algorithms, Design, Performance

Keywords:
ASIC, FPGA, communication systems, digital signal processing, fixed-point arithmetic, optimization