Conclusion

We have only barely scratched the surface on digital filters here. Go to any technical bookstore and you can easily find five hundred page books on the subject so don't be surprized that I left something out. I am listing a few literature references to provide you with starting points on other places to look in order to learn more. In this installment I have concentrated on describing the form of digital filters and not much upon how to design them. However from whats been presented so far, its pretty clear that designing a digital filter involves the manipulation of $A(Z)$ and $B(Z)$ in order to get the desired effect in $H(Z)$.

Those of you that asked for me to do an article on adaptive PID will eventually get their wish. But before we can properly understand that topic we first need to build a foundation by learning about digital filters and then adaptive digital filters. With this column we have taken the first step with our first look at nonadaptive filters.

Please don't hesitate to contact me through Forth Dimensions or via e-mail at skip@taygeta.com if you have any comments or suggestion about this or any other ForthWare column.

Skip Carter is a scientific and software consultant. He is the leader of the Forth Scientific Library project, and maintains the system taygeta on the Internet. He is also the President of the Forth Interest Group.