kantosignaalia

Kantosignaalia (the carrier signal) is a high-frequency waveform used in telecommunications to convey information by modulation. In most systems it is a sinusoidal wave with a fixed frequency fc, generated by a local oscillator and combined with the baseband signal by a modulator. The modulated waveform is transmitted through a channel, and its spectrum centers around the carrier frequency, with sidebands containing the information.

Modulation changes aspects of the carrier to encode data: amplitude modulation (AM) varies the carrier's amplitude; frequency modulation (FM) varies its frequency; phase modulation (PM) varies its phase. Digital communications often use complex modulations such as quadrature amplitude modulation (QAM) or phase-shift keying (PSK), which combine amplitude and phase changes of the carrier to represent data.

At the receiver, demodulation retrieves the baseband information by removing or reconstituting the carrier reference. Some schemes use envelope detection for AM; coherent demodulation requires a locally generated carrier to mix with the received signal. In suppressed-carrier modulation, such as double-sideband suppressed-carrier (DSB-SC), the carrier itself is not transmitted and must be recovered in processing.

Kantosignaalia thus functions as a reference and vehicle for information in both analog and digital communication systems, enabling efficient transmission across various channels and technologies.