envelopevääristymään

Envelope distortion, in Finnish envelopevääristymään, refers to a type of signal distortion that affects the amplitude modulation of a carrier wave. It is a phenomenon primarily observed in analog radio transmission systems, particularly those employing amplitude modulation (AM). Envelope distortion occurs when the demodulator circuit is unable to accurately reproduce the original modulating signal's envelope.

This distortion can manifest in several ways. One common cause is insufficient bandwidth in the receiver's intermediate frequency (IF) or audio amplifier stages. If the bandwidth is too narrow, it cannot accommodate the sidebands of the modulated signal, leading to a distorted envelope. Another cause can be non-linearities in the demodulator or amplifier stages, which introduce spurious signals that interfere with the accurate recovery of the envelope.

The consequence of envelope distortion is a degradation in the quality of the received audio signal. The sound may become muffled, distorted, or exhibit unwanted artifacts. In severe cases, the intelligibility of speech or the fidelity of music can be significantly compromised.

Envelope distortion is distinct from other forms of distortion like frequency distortion or phase distortion, although they can sometimes occur simultaneously. The primary characteristic of envelope distortion is its effect on the amplitude variations of the signal. Correcting envelope distortion typically involves ensuring adequate bandwidth and linearity in the signal processing chain of the receiver.