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SMATV is Single Master Antenna Television (or Satellite Master Antenna Television),〔 The purpose of SMATV is for supplying and controlling the number and type of channels to multiple televisions.〔 Not only TV channels but FM channels as well. It provides Reception of DBS TV/FM channels for hotels, motels, dormitories, hospitals and commercial properties with multiple tenants, schools.Using a master antenna system video signals, audio signals, decoder signals can also be distributed. It consists of single outdoor unit or antenna feeding to number of indoor units.〔 The channels accessible are independent of other users.For maintaining a good Signal to noise Ratio at all the indoor units served, a larger antenna is required. Antenna with 2 m-3m diameter. A SMATV headend is used to receive and rebroadcast Satellite TV channels throughout a property from a single satellite feed.〔 The system consist of Master Antenna , matching transformer to match the balanced antenna with unbalanced cable and amplifiers.〔 Mostly antenna have impedance around is around 300 ohm. To convert it to 75 ohm matching Transformer Balun is used. For trunk line isolation , a resistive inductive device known as splitter is used. It amplifier output is fed to splitter through coaxial trunk lines.〔 There are several methods of distribution that is often used in a SMATV headend including: * IPTV (Internet Protocol) TV Systems〔 * Com1000 Pro:Idiom Encrypted HD Headend * L-Band Satellite TV Distribution〔 Two Main approaches for distribution of digital TV signal in SMATV installations: *Transmodulation from satellite Quaternary phase shift keying QPSK to Quadrature Amplitude Modulation QAM *Direct Distribution of QPSK〔 In the United States the satellite carriers utilized to provide the satellite TV signal for SMATV headend systems are: *DIRECTV *Dish Network Smatv ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「SMATV」の詳細全文を読む スポンサード リンク
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