Good show, guys! Those are the waveforms I was seeking. I still don't know how to obtain them.
When I use an amplitude modulated signal generator, I get the expected display on my analog scope. Getting it on a digital scope is an entirely different matter, and I don't know how to do it.
Yoy told you have Tek 2440.
This is problem number 1.
Why?
Because its record length is 1024 samples aka 1k acquisition memory length.
These modern digital scopes have least thousand fold amount.
Take example.
Lets define imagined example. Scope have 1000 points memory, and display have 10 horizontal div and this memory length is equal with this display width. Now if your sample memory length is 1000 samples and your horizontal speed (aka timebase) is set so that this whole memory length take example 5ms (5 cycle 1kHz modulating signal).
In this case your timebase is set for 500us/div.
Now I ask what is sampling speed. Yes Tek 2440 max sampling speed is 500MSa/s (without talking about how they did it with using CCD).
5ms and 1000 samples. Result is 200kSa/s. With this "Nyquist limit" is 100kHz.
Now if your modulated carrier is example 1MHz it is ten times higher than Nyquist limit.
With your scope you can try set carrier freq example to 50kHz and modulate it it using 1kHz.
This you can look with your scope so that it start somehow look as conventional AM shape.
Just this short memory was big problem in old digital scopes.
(I have old times owned and used just also this Tek 2440 model. But it was so long time ago I do not remember anymore all details... somehow I think it have 50% memory lenght on display and 25% overlap in both sides... but now this my memory may be messed with what ever other old times digitals...
Think about it...
You need keep sampling frequency, in theory, least 2 (in practice usual modern DPO with Sinc interpolation, 2.5x) times higher than frequency components in your signal under test.
If need look normal AM signals this 2440 is nearly or fully hopeless. Even when it is still nice well made scope for some kind of use. Tens of years ago even with it and 2430/A we did many "miracles".