(1) The capacity of the channel through which information can pass. In audio, the rated bandwidth of a device is the portion of the frequency spectrum it can handle without significant degradation. In digital communications, the bandwidth is the amount of data that can be transmitted in a given period of time. (2) The bandwidth of a bandpass filter is the upper rolloff frequency minus the lower rolloff frequency, i.e., the frequency range in Hertz (Hz), or band, passed by the filter.