摘要
频率采样技术是 FIR数字滤波器设计的常用方法之一。使用此技术设计数字滤波器时为了使阻带内的衰减最大 ,必须确定过渡带中的样本值 ,通常采用的是查表法 ,但查表法不能保证所得数据是最优的。进化规划是一种随机优化技术 ,它可以发现全局最优解。本文介绍了进化规划在频率采样技术中的应用 ,结合 FIR数字低通、带通滤波器设计的两个例子 ,给出了算法实现的具体操作步骤和实验结果。实验数据表明 ,采用进化规划确定的频率过渡带样本值是最优的 ,设计的 FIR滤波器的频率特性优于查表法。
Frequency sampling is one of the popular methods in FIR digital filter design. In the frequency sampling method the value of transition band samples, which are usually obtained by consulting a table, must be determined in order to make the attenuation within the stopband maximal. However, the value obtained by searching for table can not be ensured to be optimal. Evolutionary programming (EP), a multi agent stochastic optimization technique, can lead to global optimal solutions for complex problems. In this paper a new application of EP to frequency sampling method is introduced. Two examples of lowpass and bandpass FIR filters are presented, and the steps of EP realization and experimental results are given. Experimental results show that the value of transition band samples obtained by EP can be ensured to be optimal and the performance of the filter is improved.
关键词
进化规划
FIR滤波器
频率采样
evolutionary programming
FIR filter
frequency sampling
