Radiotsignal

Radiotsignal is a term used to describe an electromagnetic radio frequency signal that carries information through modulation and propagation over a medium, typically free space. In practice, radiotsignals are generated by a transmitter by applying modulation to a carrier wave; the modulated signal is radiated by an antenna and travels through air or space to a receiver, which demodulates the signal to retrieve the original information.

Modulation methods can be grouped into analog and digital. Analog techniques include amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). Digital techniques include phase-shift keying (PSK), quadrature amplitude modulation (QAM), frequency-shift keying (FSK), and orthogonal frequency-division multiplexing (OFDM). The choice of modulation affects bandwidth, data rate, and resilience to noise.

Propagation depends on frequency, environment, and power. Lower frequencies can travel farther and penetrate obstacles better, while higher frequencies support higher data rates but are more prone to attenuation. Radio waves can reflect, refract, and diffract, producing multipath or shadowing effects that receivers must manage.

Radiotsignals are used in a wide range of applications, including broadcasting, cellular and Wi‑Fi networks, satellite links, radar, navigation (GPS), telemetry, and wireless sensing. Reception typically involves an antenna and a radio receiver that filters, amplifies, and demodulates the signal to recover the baseband information.

Regulatory bodies allocate frequency bands and set power limits to manage interference and spectrum use. Standards organizations define modulation schemes, encoding, and interoperability requirements. Exposure to radio-frequency energy is regulated to protect public and occupational health.

See also: Radio, Signal processing, Modulation, Wireless communication.