Stop band attenuation formula

1. What is attenuation in stop band?
2. How much attenuation is achieved in the stop band of the filter?
3. How do I increase stopband attenuation?

What is attenuation in stop band?

The stopband attenuation is the difference, in decibels, between the lowest gain in the passband and the highest gain in the stopband. Ideally this would be infinite; the higher the better.

How much attenuation is achieved in the stop band of the filter?

Depending on application, the required attenuation within the stopband may typically be a value between 20 and 120 dB higher than the nominal passband attenuation, which often is 0 dB.

How do I increase stopband attenuation?

It is possible to increase the attenuation in the stopband while keeping the same filter order and transition width by the use of weights. Weights are a way of specifying the relative importance of the passband ripple versus the stopband attenuation.