Repeater
From Free net encyclopedia
A repeater is an electronic device that receives a weak or low-level signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation.
For other meanings, see repeater (disambiguation).
The term "repeater" originated with telegraphy and referred to an electromechanical device used to regenerate telegraph signals. Use of the term has continued in telephony and data communications.
In telecommunication, the term repeater has the following standardized meanings:
- An analog device that amplifies an input signal regardless of its nature (analog or digital).
- A digital device that amplifies, reshapes, retimes, or performs a combination of any of these functions on a digital input signal for retransmission.
(Source: from Federal Standard 1037C in support of MIL-STD-188)
A digipeater is a portmanteau meaning "digital repeater", particularly used in amateur radio.
Repeaters are often used in trans-continental and trans-oceanic cables, because the attenuation (signal loss) over such distances would be completely unacceptable without them. Repeaters are used in both copper-wire cables carrying electrical signals, and in fibre optics carrying light - see Optical communications repeater.
Repeaters are used in radio communication services - see Radio Repeater. A special subgroup of those repeaters is those used in Amateur Radio - see Amateur Radio Repeater.
Repeaters are also used extensively in broadcasting, where they are known as translators or boosters. See broadcast translator for more.
When providing a point-to-point telecom link using radio, one uses repeaters in a Microwave radio relay.
In optical communications the term repeater is used to describe a piece of equipment that receives an optical signal, converts that signal into an electrical one, regenerates it, and then retransmits an optical signal. Since such a device converts the optical signal into an electrical one, and then back to an optical signal, they are often known as Optical-Electrical-Optical (OEO) repeaters.
Before the invention of electronic amplifiers, mechanically coupled carbon microphones where used as amplifiers in telephone repeaters.