Bandbredd

Bandbredd, often translated as bandwidth in English, is a term used in telecommunications to describe the capacity of a communications channel to carry information. In digital networks it refers to the maximum data rate that can be transmitted over a link, typically expressed in bits per second and scaled to kilobits, megabits, or gigabits per second. Bandwidth is a measure of potential capacity; the actual data transfer achieved over time is called throughput and can be lower due to overhead, errors, and inefficiencies.

Bandwidth can also describe the width of the frequency band occupied by a signal in analog and radio contexts. In this sense, it is measured in hertz (or kilohertz, megahertz) and represents the range of frequencies used to transmit a signal. A wider bandwidth generally allows higher data rates but may require more spectrum and more sophisticated technology.

In networks, bandwidth can be shared among users, and services may be either symmetric or asymmetric. For example, fiber connections often offer symmetric bandwidth, providing similar upload and download speeds, while some consumer copper lines or wireless links offer higher download than upload speeds. Factors affecting usable bandwidth include the physical medium, distance, noise and interference, modulation schemes, protocol overhead, and network congestion.

Measurement and planning rely on estimating nominal bandwidth provided by services and measuring real-world throughput with tests and monitoring. Theoretical limits are described by information theory, notably the Shannon-Hartley theorem, which relates bandwidth, signal-to-noise ratio, and channel capacity. Regulatory bodies manage spectrum allocation and licensing for radio bandwidth, influencing available options in wireless communications.