FIR Filter Design - Window length

Thread Starter


Joined Jun 7, 2020
How can I determine the window length for a FIR low-pass digital filter from design specifications? How does changing the window length affect the design? I am struggling to understand the role that window length plays in digital filter design.


Joined Feb 24, 2006
One way to look at windowing is to consider all the math tests you have ever taken for their effect on a grade in the current course you are taking.
If the window was large and finite, the grade you get in Calculus I as an undergraduate, would be the average of all tests going back to 1st grade arithmetic. Not really fair or useful.
If the window was equal to one then your grade for the course is equal to your grade on the Calculus I final. Not really fair and very risky to accept this result.
Some number of results in between 1 and some large number is the appropriate measure of your knowledge, and you would agree to accept this result.