What Type of Filter Do I Need?

Problem:
What type of filter do I need?

Solution:
There are some questions that have to be answered while answering this question:

1. What frequencies are wanted, and what frequencies are NOT wanted?
   
   
2. How much rejection is needed on the frequencies that are not wanted?
   
   
3. Which is important:
   
   
   • Amplitude
   • Phase
   • Delay
   
   or some combination of these?
   
   
4. Is cost more important, or is the ability to make changes?
   
   
5. What power supplies are available?
   
   
6. How do I select R's and C's for a Filter Circuit?

The designer must diligently find the answers to these questions, or it will be impossible to design a good filter. If the designer has a good idea of what type of filter is needed, they can now select the intermediate level Filter Design Wizard or the advanced level Filter Expert.