After “some” RF design courses, he decided that he had learned enough to build his own frequency-modulated continuous wave radar system. From the level of detail on this project, we’d say ...

There is yet another method of producing an AM wave; this method makes use of the fact that two phase-modulated waves may be combined in a common load to produce a wave which is amplitude-modulated.

This diagram shows an example of an AM modulated radio signal (on bottom) where the high of the radio carrier signal is change by using the signal amplitude or voltage of the audio signal (on top).