Demodulation of AM Wave

The demodulation of AM wave is done by using envelope detector. It is the most basic method of demodulation. In this method, the changes in the amplitude of the carrier is tracked by the envelope detector and thereby recovering the message signal. The output is then amplified to get proper message signal. The envelope detector uses power diode OA79 and a capacitor to track the changes. The power diode is used because the input AM signal is of very low amplitude. If we use ordinary diode, it will not detect as it is well below its threshold level. The output wave is the actual modulating message signal.