Word-Length Optimization
Kluwer Academic Publishers eBooks · 2006
This chapter has introduced several methods for automating the design of bit-parallel multiple word-length implementations of DSP systems. A lossy synthesis approach has been described, based on optimizing the area consumption of the resulting implementation, subject to constraints on the finite precision errors. Two special cases have been dealt with in detail: linear time-invariant systems, and nonlinear systems containing only differentiable nonlinearities. Two optimization methods have been proposed: an application specific heuristic, and an optimum approach based on integer linear programming. It has been demonstrated that the multiple word-length design paradigm allows a broad design space to be searched by the synthesis tools, leading to high quality results. In this chapter, system area estimation was performed using the assumption of a dedicated resource binding. However the synthesis of large systems may not be possible using this design methodology. It is often necessary to trade off the number of signal samples processed per clock period against system area through the use of operation scheduling and binding techniques. Chapter 6 addresses these problems for the case of multiple word-length systems.