用于FIR滤波器设计的共同子表达式消除新方法

提出基于等权重准则的共同子表达式消除(CSE)方法减少有限冲击响应(FIR)滤波器的硅面积与功耗开销. 该方法通过在等权重的系数位中选择子表达式, 然后消除不等权重的共同子表达式, 减少加法器数量的同时确保了加法器的平均位宽较小. 另外, 该方法基于折叠直接型结构, 相对于采用转置型结构的传统方法减少约50%的寄存器开销. 针对如何寻找最优的共同子表达式, 介绍了一种低复杂度的矩阵搜索过程. 实验结果表明, 该方法相较于已有的H-CSE方法平均减少46%的电路面积以及69%的功耗; 相较于V-CSE方法平均减少45%的电路面积以及68%的功耗.

New Common Subexpression Elimination Method for FIR Filter Design

A common subexpression elimination (CSE) method based on identical weight criteria is presented to reduce silicon area and power of finite impulse response (FIR) filters. The novelty of the method is twofold. Firstly, it only requires a few small size adders by selecting subexpressions composed of identical weight coefficient bits and then eliminating common subexpressions of different weight. Secondly, it utilizes the folded direct-form structure instead of the widely used transposed structure, thus approximately 50% registers can be reduced when compared with conventional methods. In order to find the optimum common subexpressions, a matrix search process with low complexity is introduced. Implementation examples show that our method offers an average reduction of 46% cell area and 69% power consumption over the existing H-CSE method, and an average reduction of 45% cell area and 68% power consumption over the V-CSE method.