CSD编码中共享子表达式统计特性的研究

Research on Statistical Characterization of CSD Code for the sharing of Sub-expressions

针对线性DSP变换的无乘法器实现提出主要基于移位相加、CSD编码和共享子表达式的思想,高效的数字表示系统能够降低乘法模块的复杂度。根据CSD表示法和共享子表达式的概念,研究了10位CSD编码的统计规律,得出了5项共享子表达式消除法。通过有限冲击响应滤波器(FIR)的设计与实现验证了此方法比一般的方法能减少加法器个数的结论。

This paper presents a novel technique to reduce the number of operations in Multiplierless implementations of linear DSP transforms based on shifting and adding , CSD , and sub - expressions. The complexity of multiplier blocks can be significantly reduced by using an efficient number system. First it gives the 10 bits CSD representation and definition of Sub - expressions. Then Statistical Characterization of CSD Code is studied , it found that the five - term Sub - expressions elimination . Through the design and implementation of FIR, our method will use the less adders than ordinary schemes.