This app prompts the user for Amax in dB (the maximum p-p variation in the passband of the filter), Amin (the minimum response attenuation), Wc in rad/sec (the upper end of the passband) and Ws (the upper end of the stopband). This calculates Epsilon (ripple) e as well as the Order, n. As an example, use Amax = 0.1, Amin = 60, Wc = 250 and Ws = 2000 and your results should be 0.15262 for Epsilon and 4.226 for the Order, n (see screenshot 2). If you change Ws to 500, then the Order n shoots up to 12.678 (see screenshot 3). Screenshot 1 is what you see when you first open the app, when no input has been added yet.
Butterworth Filter app
