transmiterii

Transmiterii (transmitters) are electronic devices that generate and send signals carrying information. In electronics, a transmitter converts an input signal into a form suitable for propagation over a medium, typically by modulating a carrier frequency. A basic transmitter consists of a signal source or baseband stage, a modulator, a local oscillator to produce the carrier, a power amplifier, and an output network that matches the impedance of the transmission path and the antenna or cable. The receiver demodulates the transmitted signal to recover the original information.

Transmitters differ by the type of carrier frequency and modulation. Common categories include radio-frequency transmitters for wireless communications, audio transmitters for short-range sound distribution, television transmitters, infrared and visible-light transmitters, and optical transmitters used in fiber networks. Modulation methods vary from analog approaches such as amplitude, frequency, and phase modulation to digital schemes including QAM, PSK, and OFDM, often combined with error detection and correction. Key performance factors include output power, efficiency, spectral efficiency, bandwidth, linearity, and regulatory compliance.

Transmitters are essential in broadcasting, cellular networks, Wi-Fi and other wireless standards, satellite links, radar, navigation, and industrial control systems. Because radio spectrum is regulated, transmitters must comply with national and international rules, obtain licenses where required, and use approved hardware to limit interference and ensure safety. See also transmitter versus receiver, modulation, antenna, and radio equipment standards.