Filter Design Wizard - High Pass Filters

Problem:
How does a designer implement a high pass filter?

Solution:
When a high pass filter is implemented, there will be a constant slope upward from low frequencies to high, which eventually becomes flat to a constant amplitude:


Design Procedure:

1. Begin with the desired gain for the majority of the high frequency band (the flat region).
2. Given that there will be roll-off at low frequencies, select the lowest frequency for which a 3 dB (or 70.8%) amplitude roll-off is acceptable.
3. At one tenth the frequency selected in the step above, is 20 dB (10 times rejection) acceptable, or would 40 dB (100 times rejection) be better?