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close this bookRadio and Electronics (DED Philippinen, 66 p.)
close this folder5. MODULATION OF RADIOWAVES
View the document(introduction...)
View the document5.1. THE AMPLITUDE MODULATION (AM)
View the document5.2. FREQUENCY MODULATION (FM)
View the document5.3. SIDEBANDS
View the document5.4. TRANSMISSION OF RADIOSIGNALS

5.1. THE AMPLITUDE MODULATION (AM)

As the term tells us already, here the amplitude is varied. How this is done shows fig. 27:


fig. 27

As long as the audiosignal has an amplitude of “0”, the carrierwave has its original amplitude.

As soon as the audiosignal starts to have a positive amount, the amplitude of the carrierwave will rise proportionally to the amount of the audiosignal and therefore it will have an amplitude bigger than the original carrier amplitude.

As soon as the audiosignal starts to be negatively directed, the amplitude of the carrierwave will be diminished. But keep in mind: the carrierwave may never reach an amplitude which is “0”.

The INTENSITY OF THE MODULATION can vary from case to case.

It is called the PERCENTAGE OF MODULATION?