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Title Design of a low power processor for trigonometric functions for hearing aids
Author Torp, Anders
Supervisor Nannarelli, Alberto (Computer Science and Engineering, Department of Informatics and Mathematical Modeling, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2008
Abstract Some of the functionalities in the next generation of hearing aids rely on trigonometric functions. Therefore, special purpose processors with dedicated hardware focusing on low power are required. The implementation of these functions can be based on either the CORDIC [30] algorithm or function approximation [9]. The latter requires a multiplication and is therefore not suitable for a low power implementation. The CORDIC algorithm on the hand is extremely exible as it can evaluate a large portfolio of functions [31] with little hardware. However, most of the work done so far has focused on implementations that are suitable for high-speed applications. Limited work has focused on the low power capabilities of the CORDIC algorithm. The rst part of this thesis accounts for the different CORDIC algorithms that can be used in a low power processor. Based on this work the thesis proposes a new modied version of the CORDIC algorithm called the radix-8 D-CORDIC algorithm. The new algorithm solves some of the drawbacks that the original CORDIC suffer from, such as the dependency of a scaling factor and the high number of iterations. For the new algorithm, the scaling factor is easy to evaluate, as it does not require additional logic, in addition, the required number of iterations is reduced by 67%. The algorithm is not restricted to functions in the circular coordinate system but has been extended to the hyperbolic and linear systems as well. The algorithm has been implemented in VHDL and synthesized at a clock frequency of 50 MHz with a 1.0 V 90 nm process. The processor is implemented with only 5,650 gates and has a power consumption of 0:879mW in rotation mode. In comparison with the CORDIC algorithm, this is a reduction by 32%.
Series IMM-M.Sc.-2008-33
Fulltext
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Admin Creation date: 2008-04-01    Update date: 2008-07-15    Source: dtu    ID: 213585    Original MXD