The primary function of a bandpass filter is to limit the bandwidth of the output signal to the band allocated for the transmission. In other words, the bandpass filter allows some signals to pass through while blocking others. The range of accepted frequencies is called the passband. The size or range of the passband is called the bandwidth. Some of the components of a bandpass filter are conventional coils and capacitors, or the arrangement may be made up of freely vibrating piezoelectric crystals.
Low pass and high bandpass filters are some special types of bandpass filters. These filters are primarily used to limit the bandwidth of the output signal to the band allocated for the transmission and prevent the transmitter from interfering with other stations. It is not always necessary to use a bandpass filter, but it can be sometimes used for cleaning up data and other applications.
It can be used to isolate or filter out certain frequencies that lie within a specific band or range of frequencies. It is popularly used in wireless transmitters and receivers. These filters are also popularly used in all types of instrumentation, in Seismology, Sonar, and in medical applications like Electrocardiograms, EEGs, etc. They are also used in optics, such as with lasers, LIDARS, etc.
