Toistimet

Toistimet are devices that receive a signal, process it to improve or restore its quality, and transmit it again to extend transmission distances. They are used in telecommunications, broadcasting, and data networks to overcome attenuation, noise, and channel impairments. A basic repeater comprises a receiver, a signal processing stage, and a transmitter. In analog systems it mainly amplifies the signal; in digital and optical networks it may regenerate timing and level, correct errors, and reshape the waveform.

Types include electrical repeaters for copper networks, optical repeaters (including optical amplifiers and regenerative nodes in fiber), and wireless repeaters (repeater stations that receive and retransmit signals to extend cellular, Wi‑Fi, or radio coverage). Some systems combine several functions, such as amplification plus digital regeneration or frequency translation (duplexing).

Applications: extending the reach of telephony and data services over long distances, improving mobile and wireless coverage, and distributing television or IP signals. In radio communications, repeaters operate to receive on one frequency and re-transmit on another, enabling two-way communication over obstructed terrain.

Limitations and design considerations: repeaters introduce latency and potential signal distortion if misconfigured. They require careful placement, appropriate gain, bandwidth management, and compatibility with surrounding networks to avoid interference. In fiber networks, regeneration and amplification must be matched to the optical signal’s wavelength and data rate.

History: the concept emerged with early telegraph and telephone networks and has become essential in modern networks, where repeaters extend capability across long-haul lines and wireless landscapes.