An automatic word length determination method

A method to determine the word length required by implementations of Digital Signal Processing (DSP) algorithms is presented. The method uses a C/C++ fixed-point simulation tool to model the impact of finite word length on overall accuracy. It finds a combination of quasi-optimum bit resolutions in arbitrary data flow graphs by computing dissimilarities between fixed-point and floating-point simulation results. The selected algorithm minimizes these dissimilarities and finds a combination of word lengths that meets objectives specified by the user. This method is applicable to a wide range of DSP algorithms. It was tested on 2 benchmarks, the fifth order elliptic filter and the Inverse Discrete Cosine Transform (IDCT), and arrived to known optimum solutions.