Hi,
I have a strange problem with my signal generator SDG2042X (firmware upgraded to 120MHz).
I am trying to generator a sine wave that is modulated by a square wave, or in other words a sine wave that is switched on or off in regular intervals.
The SDG2042X has an option for amplitude shift keying (ASK). This works fine for a carrier of 10kHz and a modulation of 1kHZ ASK, but it fails already for a carrier of 100kHz with the same modulation of 1kHz ASK.
Instead it doesn't seem to modulate at all, and instead I can see a 1kHz square wave modulated by a 330mHz (milliherz, so very low frequency) sine wave.
Is this a sign of the mixing limitation of my signal generator? It seems this low frequency sine wave is an artifact in general (just that the low frequency varies depending on the actually desires signal frequency).
Before that I had a similar problem, when I wanted to actually create a 10MHz sine carrier modulated by a 1kHz sine wave.
Is there any solution for this signal generator?
My goal is to create a 10MHz sine wave with a 1kHz square wave modulation.
Edit: The signal generator output is connected to the scope with a 50 Ohm BNC cable and a 50 Ohm termination.
I also noted that a pure 10MHz sine wave seems to have low frequency noise superimposed. When I zoom out, I can see a 33.3Hz sine wave.
For a pure 1MHz sine wave, I can see a 3.3Hz sine wave.