Bandwidth

Bandwidth is the width, usually measured in Hertz, of a frequency band f2 - f1. It can also be used to describe a signal, in which case the meaning is the width of the smallest frequency band within which the signal can fit. Bandwidth is related to the amount of information that can flow through a channel through the Nyquist-Shannon sampling theorem.

The bandwidth of an electronic filter is the part of the filter's frequency response that lies within 3 dB compared to the center frequency of its peak.

In control theory, the bandwidth is the frequency at which the closed-loop system gain drops to -3 dB.

The term bandwidth is also used, informally, and by extension from the above, to mean the amount of data that can be transferred through a connection in a given time period. Bandwidth is normally based on the frequencies used and the spectral spread of the information carried on the frequency.

See also

• Shannon's law
• Modulation
• Signalling schemes
• Baud rate
• Narrowband
• Broadband
• Latency
• List of device bandwidths
• Latency vs Bandwidth
• Center frequency
• Bandwidth theft