SMATV
System for distributing television signals
From Wikipedia, the free encyclopedia
SMATV (single master antenna television or satellite master antenna television),[1] is a system for supplying and controlling the number and type of communication channels, usually television channels and FM stations to multiple televisions.[2] It provides reception of DBS TV/FM channels for hotels, motels, dormitories, schools, hospitals and commercial properties with multiple tenants. Using a master antenna system video signals, audio signals and decoder signals can be distributed.
Design
It consists of single outdoor unit or antenna feeding multiple receivers.[3] Accessible channels can vary by user. Maintaining a high signal-to-noise ratio requires a larger antenna, typically 2–3 metres (6.6–9.8 ft) in diameter.
A single SMATV headend receives and retransmits satellite television channels throughout a property.[4]
The system consists of a master antenna and a matching transformer to match the balanced antenna with unbalanced cable and amplifiers.[5] Most antennas have an impedance of around 300 Ω. To convert it to 75 Ω, a matching transformer (or balun) is used. For trunk line isolation, a resistive inductive splitter is used. The amplifier output is fed to the splitter through coaxial trunk lines.[6]
Distribution
Several methods of distribution are supported via SMATV. These include:
- IPTV (Internet Protocol) TV Systems[7]
- COM1000 Pro:Idiom Encrypted HD Headend
- L-Band Satellite TV Distribution[8]
The two main approaches for distribution of digital TV signals in SMATV installations are:
- Transmodulation from satellite quaternary phase shift keying QPSK to quadrature amplitude modulation QAM
- Direct QPSK distribution[9]