Demodulera

Demodulera is the Swedish term for demodulation, the process of extracting the original information signal from a modulated carrier. It is the reverse operation of modulation, which encodes data onto a carrier by varying its amplitude, phase, or frequency. In Swedish technical usage, the noun form is demodulering; in English, the standard term is demodulation.

Demodulation methods depend on the modulation scheme used. For amplitude modulation (AM), demodulation typically employs an envelope detector to recover the baseband signal. Frequency modulation (FM) and phase modulation (PM) use frequency or phase detectors, such as discriminators or phase-locked loops. Digital modulation schemes, including quadrature amplitude modulation (QAM), phase-shift keying (PSK), and orthogonal frequency-division multiplexing (OFDM), require coherent detection with a locally generated reference carrier or non-coherent detection when a reference is unavailable. Coherent demodulation relies on carrier recovery to align phase and frequency with the received signal.

In digital communications, demodulation also involves timing recovery, symbol synchronization, and often channel equalization to mitigate distortion and interference. Demodulators may be implemented in hardware, such as radio front-ends and receivers, or in software, particularly in software-defined radio systems. Performance is typically assessed by metrics such as bit error rate, signal-to-noise ratio, and robustness to noise and interference.

Applications span radio broadcasting, telecommunications, data links, and consumer electronics, where reliable extraction of the original signal is essential for intelligibility and data integrity.