radiotransceiver

A radiotransceiver is a combined radio transmitter and receiver housed in a single device. It is designed to transmit and receive radio signals over a defined portion of the electromagnetic spectrum, sharing a common antenna interface and, in many designs, a common RF front end to enable rapid switching between transmission and reception.

Most radiotransceivers include an RF front end consisting of filters, amplifiers, a mixer, and a local oscillator. In the receiver path, the incoming RF signal is downconverted to an intermediate frequency (IF) where filtering and demodulation occur. The recovered baseband signal is then processed by audio or data stages. In the transmitter path, the baseband signal is modulated, amplified, and upconverted to RF, then sent to the antenna. A duplexer or antenna switch isolates transmit and receive paths to prevent self-interference.

Transceivers support various operating modes, such as amplitude modulation (AM), frequency modulation (FM), single-sideband (SSB), continuous wave (CW), and digital modes. They can be designed for half-duplex operation, popular in handheld and push-to-talk systems, or full-duplex operation in some base stations or via separate transmit and receive channels.

Applications range from amateur radio and commercial broadcasting to marine, aviation, and public-safety communications. Modern devices often include software-defined radio (SDR) capabilities, enabling most processing to run in software on a general-purpose processor or FPGA, allowing rapid support for new protocols and frequencies. Regulatory constraints determine allowed bands, power, and modes for a given region.