ADP5250 Noisy AWG

[JimR2]

Hi,

I just received my ADP5250, and was doing simple initial measurements on all the inputs/outputs, and am seeing significant noise (~500mV) on the AWG output. See below, is a 2V sine from the ADP5250 AWG, measured on a AD2. Regardless of cable or measurement device, the noise is consistent.

Also included is the wavegen screen of the ADP5250.

Any suggestions? I've got 2 AD2's, and a ADP3450, and have had no issues with the wavegen on those, this seems to maybe be a bad AWG? There's not much on the forum I could find on the 5250, so trying figure out whether I should send this back?

Also should add that this noise is seen, even with the AWG not running. In fact, I can turn off the ADP5250 while monitoring with the AD2, then turn back on the ADP5250, and watch the AWG output slowly float from ~0 to 500mV, at which point the noise disappears. Then when I turn on the AWG, the waveform looks reasonable (see third plot) but has a 500mV offset? Then, over time the noise re-appears, and the waveform moves back to that seen in pic#1

Regards, JimR2

  

 

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Edited April 18, 2023 by JimR2

[attila]

Hi @JimR2

First test the loopback using the ADP5250 by connecting the AWG to a Scope input. Is the signal clear ?

When connecting the ADP5250 AWG to the AD2 scope, are you using a BNC cable or a probe ? If not, is there a ground connection between the devices and is the negative scope input grounded ?

[JimR2]

Hi Attila,

 

I did the loopback you mention to the ADP5250, actually was the first thing I did. I used three different BNC shielded cables, just to be sure. The signal was noisy in all cases.

The AD2 connection also used a BNC cable. I should have mentioned I used the BNC adapter with the AD2, so there was a ground

I did not try a scope probe, it was always a BNC cable direct connection.

 

Couple thoughts,

1) I got thinking maybe the AWG output is high impedance, and needs a common mode established by the load? 

2) There is a ground terminal on the back of the unit, should I be grounding that to the same ground as the AC supply to avoid ground loops? Didn't seem like this would be necessary for a local loopback check which I did.

 

Thanks for the reply, and look forward to working through this. Hope I'm doing something wrong, seems like a nice unit, although I'm also wondering about the packaging. The unit is not in a ESD bag when it comes in the box, and it has two Styrofoam supports which slip on over each end. I noticed one of the ends completely covers the AWG and Trigger ports comes in direct contact, seems like an ESD vunerability?

 

Regards, Jim Riches

[attila]

Hi @JimR2

If the same problem persists with a loopback cable we can rule out external factors.
It could be an internal device fault on supply rails, reference... a cold solder or contact issue.

For warranty and replacement contact the support.digilent @ ni.com specifying the Date of Purchase, Seller and Purchase Order/ Web order Number.