Bandwidth

Bandwidth is the range of frequencies that can be transmitted over a network connection.

It can also refer to the amount of data that can be transmitted over a communication channel in a given amount of time, usually in a second, though this isn’t quite the definition.

You can kind of think of it like a water pipe: the wider the pipe, the more water can flow through it in a given amount of time. Similarly, the higher the bandwidth of a communication channel, the more data can be transmitted through it in a given amount of time, because more frequencies can be represented.

Units

Bandwidth is generally measured in bits per second, but its actual units are hertz (Hz), which is the number of signal changes per second. The reason for this is that the bandwidth of a communication channel is determined by the range of frequencies that it can transmit.

Frequency range

The bandwidth of a communication channel is determined by the range of frequencies that it can transmit. For example, if a communication channel can transmit frequencies between 20 Hz and 20 kHz, then its bandwidth is 20 kHz - 20 Hz = 19.98 kHz.

Bandwidth vs bit rate

The bandwidth of a communication channel is the maximum amount of data that can be transmitted over it in a given amount of time, while the bit rate is the actual amount of data that is being transmitted over the channel in a given amount of time.

Think of it like a motorway:

• The bandwidth is the speed limit of the motorway, which is the maximum speed that cars can travel on it.
• The bit rate is the actual speed of the cars on the motorway, which can be lower than the speed limit if there is traffic, or if the cars are not driving at the maximum speed, or various other things.

Bandwidth is directly proportional to bit rate.