Some Notes on Demodulation

The audio output of a detector depends upon two magnitudes which are independent each from the other. These magnitudes are the radio-frequency envelope of the input and the rectification characteristic of the detector. In problems dealing with the distortions caused by selective circuits or by the superposition of several modulated signals it becomes necessary to treat both magnitudes separately. A new method to find graphically the radio-frequency envelope for the "general modulated signal," is given. An analysis is made showing how to find the detector output if the input radio-frequency envelope and the rectification characteristic of the detector are known.