RECEIVER

A receiver is a device that accepts a signal transmitted from a source and converts it into a form usable by humans or other equipment. It is a key element in communications systems and appears in radio, television, audio, and data links. A receiver typically includes an antenna, circuitry for tuning and amplification, demodulation, and an output stage.

Common types include radio receivers (AM/FM, shortwave, or software-defined radio), television receivers, satellite and digital set-top receivers, and audio or home theater receivers that combine tuner, preamplifier, and power amplifier. In fiber optics, optical receivers convert light signals into electrical signals. Wireless receivers for standards such as Wi‑Fi, Bluetooth, cellular, and NFC provide the interface to end-user devices. Some receivers are dedicated front ends, while others are multi-purpose units with digital signal processing.

Key attributes include sensitivity (the smallest signal it can detect) and selectivity (its ability to separate desired signals from nearby channels). Other important factors are dynamic range, noise figure, linearity, and interference rejection. In analog receivers, demodulation recovers the original information; in digital receivers, analog-to-digital conversion and digital signal processing extract the data. The block diagram typically includes an RF front end, mixer and local oscillator, intermediate frequency stages, demodulator, decoder, and output interface.

The term is often used as the counterpart to transmitter, referring to the end point of a communication link. In broader senses, "receiver" may describe any sensor or detector that captures a signal, including optical, infrared, or radio-frequency sensors.