How to reprodoce dave's waveform

[SteveRosenlund]

Hi there,

I cannot for the life of me figure out how to reproduce the wave form Dave uses on most of his scope reviews.  I know it's  a simple AM modulation signal, but how do i get that to come out of my Siglent SDG2042X AWG?  Picture below.

[Paul Rose]

Use MOD -> Type -> AM to select modulation

Set Frequency to your carrier frequency ( e.g. 1 MHz )

Set AM Freq to your modulation frequency ( e.g. 1kHz )

Set AM Depth to 100%

Set offset to 0

The "AM Frequency" (modulation) will define the "envelope" that you see on the scope display

The "Frequency" (carrier) will define the higher frequency that gets drawn as the "blurry" gradient on the scope.

Your horizontal time base on your scope should be set according to your modulation frequency, so you can see the envelope.  The carrier frequency will be too high to see as a sine wave, it will be seen as the blurry gradient.

If you set the horizontal time base on the scope according to the carrier frequency, you will just see a regular sine wave.  The modulation frequency is too low to be visible.

 

[SteveRosenlund]

Hey thanks!  I’ll try that out when I get home from this Halloween party that’s so fun I’m on my phone looking at forums. 

[alsetalokin4017]

I used HP8640B. Is that cheating?   

[Paul Rose]

I used HP8640B. Is that cheating?   

I have one of those, but I have to keep it on the floor.  It is too heavy for my bench 

[alsetalokin4017]

Heh... mine lives on its own little table over in the corner. They don't call them "boat anchors" for nothing!

Someone gave me this one; it needed some minor repairs which I performed.

The only thing I ever use it for is when someone asks me to show an AM modulated sine wave at 100 MHz, or something like that. I suppose some day I'll have to toss it in a dumpster. I shudder to think what it cost when it was new.

[vk6zgo]

I used HP8640B. Is that cheating?   

That is not a very useful way of displaying an AM waveform.
The time/div setting should normally be equal to, or longer than the duration of one cycle of the modulating waveform.

[drussell]

Heh... mine lives on its own little table over in the corner. They don't call them "boat anchors" for nothing!

Someone gave me this one; it needed some minor repairs which I performed.

The only thing I ever use it for is when someone asks me to show an AM modulated sine wave at 100 MHz, or something like that. I suppose some day I'll have to toss it in a dumpster. I shudder to think what it cost when it was new.

I hope I'm near the dumpster someone tosses one of those into someday, I'd love to get my hands on one, even if it does weigh 50 pounds! 

(Or better yet, skip the dumpster, just have someone give me one needing minor repairs or something....  you lucky boat anchor finders, you....    )

[Mr. Scram]

I used HP8640B. Is that cheating?   

That doesn't seem to be quite the same yet.