Harsh? Why not explain what is wrong
no i'm trying to be gentle actually, since most newcomers will get hot when told the truth and they will come with their machine gun theory book. look, my AD9850...
picture 1) very nice!
picture 2) so so
picture 3) well?
bear in mind this is sampled 25 points per cycle (40MHz @ 1GSps)
picture 4) how a theoritical 25pts sine should looks like.
conclusion: "average" will closely resemble perfect sine. "single capture" (picture 3) is the truth. if we want talk sweet and sugar, we show "average", if we want to talk the truth grain and salt, show "single capture", "average" is nice, but not truth. and lastly... use 1X attenuation 50 ohm Z coax with 50 ohm termination at the scope end when testing, thats the de-facto standard way... google it its too long, fwiw..
picture 5) when superimposed theory and the truth... fwiw..