AMdemodulaatorid

AMdemodulaatorid, also known as Amplitude Modulation demodulators, are electronic circuits used to extract the original audio or data signal from an amplitude-modulated (AM) radio wave. When an audio signal modulates an AM carrier wave, the amplitude of the carrier wave varies in accordance with the audio signal's instantaneous amplitude. The demodulator's function is to reverse this process, effectively recovering the original modulating signal.

The most common type of AM demodulator is the envelope detector. This circuit typically consists of a diode and a capacitor. The diode rectifies the incoming AM signal, allowing current to flow in only one direction. This rectification process removes the negative halves of the modulated carrier wave. The capacitor then smooths out the rectified pulses, forming an envelope that closely follows the variations in the amplitude of the original AM signal. This smoothed-out signal is essentially the recovered modulating signal, though it may still contain residual carrier frequency components.

Further filtering, often achieved with a resistor-capacitor (RC) low-pass filter, is usually employed to remove any remaining high-frequency components from the carrier wave, leaving behind the desired audio or data signal. While simple and effective, envelope detectors are susceptible to noise and fading, which can distort the demodulated output. More sophisticated AM demodulators exist, such as synchronous detectors, which offer improved performance but are more complex. AM demodulators are fundamental components in AM radios and other communication systems that utilize amplitude modulation.