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A single-frequency network or SFN is a broadcast network where several transmitters simultaneously send the same signal over the same frequency channel. Analog AM and FM radio broadcast networks as well as digital broadcast networks can operate in this manner. SFNs are not generally compatible with analog television transmission, since the SFN results in ghosting due to echoes of the same signal. A simplified form of SFN can be achieved by a low power co-channel repeater, booster or broadcast translator, which is utilized as gap filler transmitter.

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  • Xarxa de freqüència única
  • Gleichwellennetz
  • Single-frequency network
  • Red de frecuencia única
  • Réseau isofréquence
  • Isofrequenza
  • 單頻網
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  • La Xarxa de freqüència única (SFN o Single Frequency Network) és un tipus de radiodifusió on diferents transmissors emeten el mateix senyal en el mateix canal de freqüència. Anàlogament amb els sistemes de radiodifusió d'FM i AM, els sistemes de radiodifusió digital també poden operar d'aquesta manera. La Televisió Digital Terrestre (TDT o DVB-T) fa servir aquest concepte per tal d'aconseguir un millor aprofitament de l'espectre en les bandes de televisió en comparació amb el que es feia servir en televisió analògica, que era Xarxa de freqüència múltiple (MFN o Multiple Frequency Network).
  • Una red de frecuencia única o SFN (por su acrónimo en idioma inglés Single-Frequency Network) es una red de difusión donde varios transmisores envían simultáneamente la misma señal a través del mismo canal de frecuencia.
  • Un réseau isofréquence est un réseau constitué d'émetteurs radio opérant sur une fréquence unique dans une région déterminée. Il peut typiquement s'agir d'émetteurs de radio ou de télévision numérique. Sur un plan international, les réseaux isofréquence doivent faire l'objet d'accord spécifiques, notamment pour traiter l'agencement spectral des zones frontalières.
  • A single-frequency network or SFN is a broadcast network where several transmitters simultaneously send the same signal over the same frequency channel. Analog AM and FM radio broadcast networks as well as digital broadcast networks can operate in this manner. SFNs are not generally compatible with analog television transmission, since the SFN results in ghosting due to echoes of the same signal. A simplified form of SFN can be achieved by a low power co-channel repeater, booster or broadcast translator, which is utilized as gap filler transmitter.
  • Nella tecnica della radiodiffusione, con il termine isofrequenza si intende letteralmente sulla stessa frequenza. In pratica, con questa tecnica, una determinata emittente, sia essa analogica che digitale irradia lo stesso segnale da più postazioni, in maniera contemporanea e sulla stessa frequenza. Ciò permette di ricevere il segnale in qualunque luogo della zona di copertura senza che si rendano necessarie variazioni alla sintonia del ricevitore.
  • 單頻網(Single-Frequency Network,SFN)是一種廣播網路,易言之,即數個傳送器透過同個頻率頻道同時傳送同個訊號。 類比的FM與AM音訊廣播網以及數位廣播網在SFN中可以同時運作;但類比電視播送已證明很難在SFN中達成,因為SFN會導致同個訊號而產生鬼影(多重影像)。 SFN的簡化型態,可由低電量的共同頻道強波器、中繼器或是廣播傳送器來達成。 SFN的目標主要是有效率地使用無線電頻譜,使得廣播與電視頻道的數量可以比傳統的(MFN)更多。SFN相較於MFN來說也可以增加涵蓋率與減少斷訊,因為總數接收訊號的強度可以增加傳送器中間的位置。 SFN的架構有點像非廣播的無線傳輸(例如蜂窩式行動網路以及無線的電腦網路),稱之為傳輸器巨分集、CDMA的軟性換手傳遞(soft handoff)以及動態單頻網(Dynamic Single Frequency Networks,DSFN)。 OFDM使用在無線數位電視廣播系統的DVB-T(歐洲與其他國家使用)、ISDB-T(日本與巴西使用)中。OFDM也廣泛使用在數位音訊廣播系統中,包含DAB、以及T-DMB。總而言之,這些系統也適用於SFN中。 透過垂直頻道的編碼使用,MFN可以用SFN的姿態出現在ATSC的閱聽眾前。 在如下的OFDM調變方式里,使用SFN消除自我干擾:
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