I don't manage to understand why in the patch *helpBrowser>Manuals>PlayNow>ring-modulator.pd* the author is speaking about Amplitude Modulation.

For me :

[vslider 1-10]
|
[osc~]
|
[*~ 1000]
|
[osc~]

is a frequency modulation with a carrier frequency at 0Hz and with an index of modulation equal to 1000.
no ?

the thing you posted is frequency modulation.

ring mod is fast amplitude modulation

ok, and the author don't use the term amplitude modulation but "amplitude modulators", he just specified the object [*~] I think, not the objects used before it.
thanks.