基于FPGA的电子鼻中Sigmoid函数分区间线性逼近实现

Sigmoid function in FPGA-based electronic nose implemented by inter-partition linear approximation

对表驱动线性逼近方法实现的sigmoid函数进行分析,在Matlab中对其仿真,得到误差曲线。该误差曲线在不同区间内误差相差较大,由此提出分区间线性逼近法实现sigmoid函数。不同区间采用不同的插值间隔,以尽量减少ROM资源的使用。经Matlab仿真,得到改进后的误差曲线,其最大误差未增大。最后在Quartus II中建立工程,调用Modlesim进行RTL仿真,证明该方法可行。

sigmoid function for table-driven linear approximation method implementation was analyzed. The error curve was got by simulating in Matlab. The margin of error is different in different sections. It would be a feasible method that different sections with different interpolation intervals to minimize the use of Read-Only-Memory（ ROM）. At last,this method is verified by Matlab simulation and Register-Transfer-Level（ RTL） simulation. This method is useful and feasible.