The applications of digital filters are two-fold: (1) separating combined signals, and (2) restoring distorted signals. Though, analog filters can be used for these purposes, however digital filters have found to shown superior results.
Digital filters are core of digital signal processing (DSP) applications. In fact, the main for DSP becoming so popular is because of their extraordinary performance. As highlighted earlier the two-fold uses of filters are signal separation and signal restoration. When there is contamination with noise, interference and other signals, then signal separation becomes essential. For instance, while getting the electrical activity of a baby in the womb using EKG. There is a very high possibility of picking the signal mixed with that of the mother’s breathing and heartbeat. Hence, a filter serves as a critical member for separating and analysing the signals individually 5.
Similarly, signal restoration is another important application; when the signal is distorted in some way. For instance, background noise can be filtered from an audio recording done using a poor equipment. Another application is in deblurring of an image captured by an improperly focussed or a shaky camera
A low-pass filter (LPF), as the name indicates, allows signals with a frequency lower than cutoff frequency to pass, and attenuates the ones higher than that. The exact frequency response of the filter is dictated by its design.
There are various varieties of low pass filters, and some of the important one’s that we’ll discuss are –