MSE FIR digital filter design example N=21
<a href="https://en.wikipedia.org/wiki/zh:User:Hou-Sheng_Chen" class="extiw" title="w:zh:User:Hou-Sheng Chen">Hou-Sheng Chen</a> at <a href="https://en.wikipedia.org/wiki/zh:" class="extiw" title="w:zh:">Chinese Wikipedia</a>
<span class="int-own-work" lang="en">Own work</span>