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Sideband

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	Topics Sideband Topic Home In radioRadio Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of light.... communications, a sideband is a bandBand (radio) A band is a small section of the spectrum of radio communication frequencies, in which channels are usually used or set asid... of frequencies higher than or lower than the carrier frequencyCarrier frequency Carrier frequency is a term used to designate the nominal frequency of a carrier wave, the center frequency of a frequency ... , containing power as a result of the modulationModulation Modulation is the process of varying a carrier signal in order to use that signal to convey information.... process. The sidebands consist of all the FourierFourier Fourier could refer to:Joseph Fourier, a French mathematician and physicist... components of the modulated signal except the carrier. All forms of modulation produce sidebands. Amplitude modulation of a carrier waveCarrier wave A carrier wave, or carrier* is a waveform that is modulated to represent the information to be transmitted.... 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 transmissionTransmission (telecommunications) In telecommunications, transmission is the act of transmitting electrical messages.... , 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 subcarrierSubcarrier A subcarrier is separate analog or digital signal carried on a main radio transmission, which carries extra information such... . The receiver locally regenerates the subcarrier by doubling a special 19 kHz pilot tonePilot signal In telecommunication, a pilot is a signal, usually a single frequency, transmitted over a communications system for supervis... , but in other DSB-SC systems the carrier may be regenerated directly from the sidebands by a Costas loopCostas loop In telecommunication, a Costas loop is a phase-locked loop used for carrier phase recovery from suppressed-carrier modulatio... 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 televisionTelevision Television is a telecommunication system for... broadcastingBroadcasting Broadcasting is the distribution of audio and/or video signals to a number of recipients that belong to a large group.... , 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 HF radio. Since the sidebands are mirror images, which sideband is used is a matter of convention. In amateur radioAmateur radio Amateur radio, often called ham radio, is a hobby and public service enjoyed by about 3 million people throughout the ... , LSB is traditionally used below 10 MHz and USB is used above 10 MHz. In SSB, the carrier is suppressed, significantly reducing the electrical powerElectric power Summary Electric power is defined as the amount of work done by an electric current in a unit time. ... (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 oscillatorBeat frequency oscillator A beat frequency oscillator or BFO in radio telegraphy, is a dedicated oscillator used to create an audio frequency si... must be used at the receiverReceiver (radio) In radio terminology, a receiver is an electronic circuit that receives a radio signal from an antenna and decodes the signa... to reconstitute the carrierCarrier wave A carrier wave, or carrier is a waveform that is modulated to represent the information to be transmitted.... . Another way to look at an SSB receiver is as an RF-to-audio frequency translator: 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 interfereInterference Interference is the superposition of two or more waves resulting in a new wave pattern.... with adjacent channelAdjacent channel In broadcasting an adjacent channel is an AM, FM, or TV channel that is next to another channel.... s. The part of the sideband that would overlap the neighboring channel must be suppressed by filterElectronic filter Electronic filters are electronic circuits which perform signal processing functions, specifically intended to remove unwant... s, before or after modulation (often both). In Broadcast bandBroadcast band The broadcast band is actually several chunks of the radio spectrum.... frequency modulationFrequency modulation Frequency modulation is a form of modulation which represents information as variations in the instantaneous frequency of a... (FM), subcarrierSubcarrier A subcarrier is separate analog or digital signal carried on a main radio transmission, which carries extra information such... 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 deviationDeviation The word deviation means an act of deviating, or the amount by which something has deviated, or the route followed by a devi... and ±100 kHz channelChannel (communications) Channel, in communications, refers to the medium used to convey information from a sender to a receiver.... boundaries. Amateur radioAmateur radio Amateur radio, often called ham radio, is a hobby and public service enjoyed by about 3 million people throughout the ... and public service FM transmitters generally utilize ±5 kHz deviation. See also Single-sideband modulationSingle-sideband modulation Single-sideband modulation is a refinement of the technique of amplitude modulation designed to be more efficient in its us... for more technical information about sideband modulation