EURASIP Journal on Applied Signal Processing,
on Design Methods for DSP Systems,
vol. 2006, special no. 5, 14 pages, Article Id 92849, 2006.
Wordlength Optimization Using Sensitivity Information
Brian L. Evans
Wireless Networking and
The University of Texas at Austin,
Austin, TX 78712 USA
Many digital signal processing algorithms are first developed in
floating point and later converted into fixed point for digital
During this conversion, more than 50% of the design time may be
spent for complex designs, and optimum wordlengths are searched
by trading off of hardware complexity for arithmetic precision at
We propose a fast algorithm for searching for an optimum wordlength.
This algorithm uses sensitivity information of hardware complexity
and system output error with respect to the signal wordlengths, while
other papers use only one of the two sensitivities.
This paper presents various optimization methods, and compares sensitivity
Wordlength design case studies for a wireless demodulator show that
the proposed method can find an optimum solution in one of fourth
the time that the local search method takes.
In addition, the optimum wordlength searched by the proposed method
has 30% lower complexity than the sequential search method in wireless
demodulators. Case studies demonstrate the proposed method is robust
for searching optimum wordlength in a non-convex space.
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Last Updated 05/21/06.