In telecommunication, Carson's bandwidth rule defines the approximate bandwidth requirements of communications system components for a carrier signal that is frequency modulated by a continuous or broad spectrum of frequencies rather than a single frequency. Copy of the original phone of Graham Bell at the Musée des Arts et Métiers in Paris Telecommunication is the transmission of signals over a distance for the purpose of communication. ... Bandwidth is a measure of frequency range and is typically measured in hertz. ... In telecommunication, a communications system is a collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment (DTE) usually capable of interconnection and interoperation to form an integrated whole. ... A carrier wave, or carrier is a waveform (usually sinusoidal) that is modulated (modified) to represent the information to be transmitted. ... In information theory, a signal is the sequence of states of a communications channel that encodes a message. ... Frequency modulation (FM) is a form of modulation which represents information as variations in the instantaneous frequency of a carrier wave. ...

Carson's bandwidth rule is expressed by the relation CBR = 2(Δf + f _m) where CBR is the bandwidth requirement, Δf is the peak frequency deviation, and f _m is the highest modulating frequency.

For example, an FM signal with 5kHz peak deviation, and a maximum audio frequency of 3kHz, would require a bandwidth of approximately 2(5+3) = 16kHz. A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ...

Carson's bandwidth rule is often applied to transmitters, antennas, optical sources, receivers, photodetectors, and other communications system components. Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ... A Yagi-Uda antenna An antenna or aerial is an electrical device designed to transmit or receive radio waves or, more generally, any electromagnetic waves. ... In radio terminology, a receiver is an electronic circuit that receives a radio signal from an antenna and decodes the signal for use as sound, pictures, navigational-position information, etc. ... Photosensors or photodetectors appear in several varieties: Photoresistors or Light Dependant Resistors (LDR) which change resistance when illuminated Photovoltaic cells or solar cells which produce a voltage and supply an electric current when illuminated Photodiodes which can operate in photovoltaic mode or photoconductive mode Phototubes containing a photocathode which emits...

The main drawback in Carson's rule is that it cannot be used when the modulated message signal is a square wave. This is attributed to the symmetry issues of the spectrum.