Sideband

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Sideband

In radio

Radio

Radio is the transmission of signals, by modulation of electromagnetic radiation with frequency below those of visible light.Electromagnetic radiation radio propagation by means of oscillating electromagnetic fields that pass through the air and the vacuum of space....
communications, a sideband is a band

Band (radio)

A band is a small section of the electromagnetic spectrum of radio communication frequency, in which channel are usually used or set aside for the same purpose....
of frequencies higher than or lower than the carrier frequency

Carrier frequency

Carrier frequency is a term used to designate:* The Real versus nominal value frequency of a carrier wave* The center frequency of a frequency modulation signal...
, somehow containing power as a result of the modulation

Modulation

In telecommunications, modulation is the process of varying a Periodic function waveform, i.e. a tone, in order to use that signal to convey a message, in a similar fashion as a musician may modulate the tone from a musical instrument by varying its volume, timing and Pitch ....
process. The sidebands consist of all the Fourier

Fourier

Fourier may refer to:*Charles Fourier , a French utopian socialist thinker*Joseph Fourier , a French mathematician and physicist**Mathematics, physics, and engineering terms named in his honor for his work on the concepts underlying them:...
components of the modulated signal except the carrier. All forms of modulation produce sidebands.

Amplitude modulation of a carrier wave

Carrier wave

In telecommunications, a carrier wave, or carrier is a waveform that is Modulation with an signal for the purpose of conveying information....
normally results in two mirror-image sidebands.

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Encyclopedia

In radio

Radio

Band (radio)

Carrier frequency

Modulation

Fourier

Carrier wave

In telecommunications, a carrier wave, or carrier is a waveform that is Modulation with an signal for the purpose of conveying information....
normally results in two mirror-image sidebands. The signal components above the carrier frequency constitute the upper sideband (USB) and those below the carrier frequency constitute the lower sideband (LSB). In conventional AM transmission

Transmission (telecommunications)

In telecommunications, transmission is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired or wireless....
, the carrier and both sidebands are present, sometimes called double sideband amplitude modulation (DSB-AM).

In some forms of AM the carrier may be removed, producing double sideband with suppressed carrier (DSB-SC). An example is the stereophonic difference (L-R) information transmitted in FM stereo broadcasting on a 38 kHz subcarrier

Subcarrier

A subcarrier is a separate analog or digital signal carried on a main radio transmission , which carries extra information such as voice or data....
. The receiver locally regenerates the subcarrier by doubling a special 19 kHz pilot tone

Pilot signal

In telecommunications, a pilot is a Signalling , usually a single frequency, transmitted over a communications system for supervisory, control, equalization, continuity, synchronization, or reference purposes....
, but in other DSB-SC systems the carrier may be regenerated directly from the sidebands by a Costas loop

Costas loop

In telecommunication, a Costas loop is a phase-locked loop used for carrier wave phase Carrier recovery from suppressed-carrier modulation signals, such as from double-sideband suppressed carrier signals....
or squaring loop. This is common in digital transmission systems such as BPSK where the signal is continually present.

If part of one sideband and all of the other remain, it is called vestigial sideband, used mostly with television

Television

Television is a widely used telecommunication mass-media for transmitting and receiving moving , either monochrome or color, usually accompanied by sound....
broadcasting

Broadcasting

Broadcasting is distribution of Sound and/or video Signalling s which transmit programs to an audience. The audience may be the general public or a relatively large sub-audience, such as children or young adults....
, which would otherwise take up an unacceptable amount of bandwidth. Transmission in which only one sideband is transmitted is called single-sideband transmission or SSB. SSB is the predominant voice mode on shortwave radio

Shortwave

Shortwave radio operates in the frequency range of 3,000 kHz to 30,000 kHz . In radio, short wavelength corresponds to high frequency given the inverse relationship between frequency and wavelength, thus, ?shortwave radio? is denominated so, because its wavelengths are shorter than the long wave-lengths used in early radio communications; m...
other than shortwave broadcasting

Shortwave

Amateur radio

Amateur radio, often called Etymology of ham radio, is both a hobby and a service in which participants, called "hams," use various types of radio communications equipment to communicate with other radio amateurs for Public services, recreation and self-training....
, LSB is traditionally used below 10 MHz and USB is used above 10 MHz.

In SSB, the carrier is suppressed, significantly reducing the electrical power

Electric power

Electric power is defined as the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt .When electric current flows in a circuit, it can transfer energy to do mechanical work or work ....
(by up to 12 dB) without affecting the information in the sideband. This makes for more efficient use of transmitter power and RF bandwidth, but a beat frequency oscillator

Beat frequency oscillator

A beat frequency oscillator or BFO in radio telegraphy, is a dedicated oscillator used to create an audio frequency signal from carrier wave transmissions to make them audible, as they are not Broadcasting as such....
must be used at the receiver

Receiver (radio)

This article is about a radio receiver, for other uses see Radio .A radio receiver is an electronics circuit that receives its input from an antenna , uses electronic filters to separate a wanted radio signal from all other signals picked up by this antenna, electronic amplifier it to a level suitable for further processing, and finally...
to reconstitute the carrier

Carrier wave

In telecommunications, a carrier wave, or carrier is a waveform that is Modulation with an signal for the purpose of conveying information....
. Another way to look at an SSB receiver is as an RF-to-audio frequency transposer

Transposition (music)

In music transposition refers to the process of moving a collection of notes up or down in pitch by a constant interval . For example, one might transpose an entire piece of music into another Key ....
: in USB mode, the dial frequency is subtracted from each radio frequency component to produce a corresponding audio component, while in LSB mode each incoming radio frequency component is subtracted from the dial frequency.

Sidebands can also interfere

Interference

In physics, interference is the addition of two or more waves that result in a new wave pattern.Interference usually refers to the interaction of waves which are correlated or Coherence with each other, either because they come from the same source or because they have the same or nearly the same frequency....
with adjacent channel

Adjacent channel

In Broadcastinging an adjacent channel is an Amplitude modulation, FM, or television channel that is next to another channel . First-adjacent is immediately next to another channel, second-adjacent is two channels away, and so forth....
s. The part of the sideband that would overlap the neighboring channel must be suppressed by filter

Electronic filter

Electronic filters are electronic circuits which perform signal processing functions, specifically to remove unwanted frequency components from the signal and/or to enhance wanted ones....
s, before or after modulation (often both). In Broadcast band

Broadcast band

Broadcast band commonly refers to several segments of the radio spectrum. In the U.S. the major broadcast bands are:In Europe, North Africa and Asia, longwave radio frequencies between 153 and 281 kHz are used for domestic and international broadcasting....
frequency modulation

Frequency modulation

In telecommunications, frequency modulation conveys information over a carrier wave by varying its frequency . In analog signal applications, the instantaneous frequency of the carrier is directly proportional to the instantaneous value of the input signal....
(FM), subcarrier

Subcarrier

A subcarrier is a separate analog or digital signal carried on a main radio transmission , which carries extra information such as voice or data....
s above 75 kHz are limited to a small percentage of modulation and are prohibited above 99 kHz altogether to protect the ±75 kHz normal deviation

Deviation

A deviation is a difference or the route followed by a different choice.Deviation can refer to:* Deviation , the difference between the value of an observation and the mean of the population in mathematics and statistics....
and ±100 kHz channel

Channel (communications)

Channel, in communications , refers to the :wikt:medium used to information transfer information from a sender to a receiver ....
boundaries. Amateur radio

Amateur radio

Amateur radio, often called Etymology of ham radio, is both a hobby and a service in which participants, called "hams," use various types of radio communications equipment to communicate with other radio amateurs for Public services, recreation and self-training....
and public service FM transmitters generally utilize ±5 kHz deviation.

Sideband

See also