Products > Test Equipment
Siglent SDG1032 Amplitude not constant when sweeping
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eTobey:

--- Quote from: ebastler on May 19, 2024, 09:51:30 am ---... but it seem like you still have a length of two loose wires as part of your connection, which obviously don't have 50 Ohm impedance and may cause reflections.

There are dedicated adapters for that, e.g. here, or they come included with some scope probes. (I got mine with the Testec probes I bought a few years ago.) But in a pinch you can improvise by plugging the bare probe tip into the BNC jack and making the ground connection with a piece of wire or foil.

--- End quote ---

Look at the picture again. Its in plain sight  ;-)

I had that adapter, and i tried it, it looks better then, but i would like to use that signal of the gen, and not just measure it. I gues the right thing would then to build my own ouput stage, that would limit problematic voltages, and cope with the termination. But i want to finish my project and dont do new ones.  :o

Maybe there is something to buy like this?
ebastler:

--- Quote from: eTobey on May 19, 2024, 10:06:13 am ---Look at the picture again. Its in plain sight  ;-)

--- End quote ---

Sorry, we may be misunderstanding each other. What is in "plain sight" for me in the photo is

- a long red/black wire which I assume comes from the generator,
- a resistor at the end of that wire,
- a pice of cardboard (?) in a crocodile clip,
- a probe lying next to it, apparently unconnected to anything.

So I am not sure at all how you had your probe connected to the generator.  ::)

Edit: Oh, and if you need to deliver that 1..30 MHz sweep to your device under test, you need to provide a proper input for it on the DUT. (BNC, 50 Ohm terminated.) Then measure with the high-impedance probe tip right where the signal enters your DUT.  I was under the impression that the sweep was just for performance/stability testing of the generator, not related to a current project.

Edit²: Or did your "in plain sight" refer to the scope probe, which does look like a Testec probe? So you have one of those BNC adapters? If so, I would love to see a frequency sweep measured directly at the generator's BNC output, with nothing else connected. (And the same for the spurious voltages you see when powering off the generator, discussed in the other thread.) It's the cleanest connection you can make with the equipment at hand.
eTobey:

--- Quote from: ebastler on May 19, 2024, 10:38:38 am ---
--- Quote from: eTobey on May 19, 2024, 10:06:13 am ---Look at the picture again. Its in plain sight  ;-)

--- End quote ---

Sorry, we may be misunderstanding each other. What is in "plain sight" for me in the photo is

- a long red/black wire which I assume comes from the generator,
- a resistor at the end of that wire,
- a pice of cardboard (?) in a crocodile clip,
- a probe lying next to it, apparently unconnected to anything.

So I am not sure at all how you had your probe connected to the generator.  ::)

Edit: Oh, and if you need to deliver that 1..30 MHz sweep to your device under test, you need to provide a proper input for it on the DUT. (BNC, 50 Ohm terminated.) Then measure with the high-impedance probe tip right where the signal enters your DUT.  I was under the impression tjhat the sweep was just for performance/stability tesintg of the generator, not related to a current project.

--- End quote ---
That resistor is the termination, i thought i mentioned it. Should have mentioned it again.

Didnt notice, that the cardboard did actually hide the pin header (where the probe would go) on that angle. It would not stick in there on its own.


Aldo22:

--- Quote from: ebastler on May 19, 2024, 10:38:38 am ---Edit: Oh, and if you need to deliver that 1..30 MHz sweep to your device under test, you need to provide a proper input for it on the DUT. (BNC, 50 Ohm terminated.)

--- End quote ---
Or SMA with adapter, which is handier.
I always try to keep the distances as short as possible so that there is less noise etc.  ;)
eTobey:

--- Quote from: Aldo22 on May 19, 2024, 11:24:08 am ---
--- Quote from: ebastler on May 19, 2024, 10:38:38 am ---Edit: Oh, and if you need to deliver that 1..30 MHz sweep to your device under test, you need to provide a proper input for it on the DUT. (BNC, 50 Ohm terminated.)

--- End quote ---
Or SMA with adapter, which is handier.
I always try to keep the distances as short as possible so that there is less noise etc.

--- End quote ---
Are you supporting the cable? If not, you put a lot of stress on the right side SMA adapter.

What is this board??
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