The selectivity of a filter describes the filters ability to pass frequencies of a specified range and reject all other frequencies that may/may be adjacent in the frequency spectrum. It is essentially a performance measurement for a particular filtered channel.What is the selectivity of a filter?
It is expressed as the ratio of the signal strength of the frequencies passed against the signal strength of a similar frequency on an adjacent frequency which is filtered. It is typically written as decibels (dB).What is the mathematical expression for selectivity?