Passband
![Unrestricted signal (upper diagram). Bandpass filter applied to signal (middle diagram). Resulting passband signal (bottom diagram). A(f) is the frequency function of the signal or filter in arbitrary units.](/Images/godic/202502/01/Passband_schematic32021.png")
A passband is the range of frequencies or wavelengths that can pass through a filter. For example, a radio receiver contains a bandpass filter to select the frequency of the desired radio signal out of all the radio waves picked up by its antenna. The passband of a receiver is the range of frequencies it can receive.