frekvensområde

Frekvensområde is a term used in physics, engineering and telecommunications to denote the range of frequencies that a device, signal, or system can contain, transmit, receive, or operate within. It is specified by a lower bound f_min and an upper bound f_max, and is usually expressed in hertz (Hz) or larger units such as kHz, MHz, or GHz.

Frekvensområde is related to, but distinct from, bandwidth. Bandwidth is the width of the range, calculated as f_max minus f_min. A frequency band refers to a named or allocated range used for a particular purpose, for example a communication standard or broadcast band. The frequency response of a system describes how its amplitude or phase varies across its frekvensområde.

Applications vary across fields. In audio, the audible frekvensområde is typically about 20 Hz to 20 kHz. In radio and telecommunications, devices specify a frekvensområde corresponding to the frequencies they can transmit or receive, such as a receiver with a 700 MHz–800 MHz frekvensområde. In digital systems, the usable frekvensområde is limited by the sampling rate, with the Nyquist frequency defining the highest representable frequency as half the sampling rate.

Measurement and design considerations are central to managing frekvensområde. Engineers determine it using instruments like spectrum analyzers and network analyzers. When designing filters, the desired frekvensområde is achieved by selecting appropriate passbands and stopbands. Regulatory and environmental constraints may also limit the usable frekvensområde in practice.