Welcome to the Filters!


In signal processing, A Filter is a Device or Process that removes some unwanted components or features from a signal. Filtering is a class of signal processing, the defining feature of filters being the complete or partial suppression of some aspect of the signal. Most often, this means removing some frequencies or frequency bands.

There are many different bases of filters, including center frequency, cutoff frequency, frequency response, stopband frequency, -3dB Frequency (f3dB), bandwidth (β or B.W.), insertion loss, quality factor (Q), ripple, passband ripple, return loss, stopband suppression, time domain, frequency domain, custom, delay and so on. Read more about filter info, here it is.


Learn about Various Types of Filters here. The use of a digital filter can be broken into three categories: time domain, frequency domain and custom. In addition, the four primary types of filters include the Low-pass Filter, the High-pass Filter, the band-pass filter, and the notch filter (or the band-reject or band-stop filter), and they can be active or passive filters.

Certain filters may be specified by family and bandform, and each family of filters can be specified to a particular order. An ideal filter has full transmission in the pass band, complete attenuation in the stop band, and an abrupt transition between the two bands, but this filter has infinite order. Learn more about Classification of Filters from this page.


In electronics, there are many practical applications for filters, such as radio communications, DC power supplies, audio electronics, analog-to-digital conversion, etc.

One important application of filters is in telecommunication, and multilevel and multiphase digital modulation systems require filters that have flat phase delay. In a word, filters serve a critical role in many common applications. This page is giving more Professional Filter Applications to readers.

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