Author Topic: Rigol 1054Z user-error or oscilloscope problem?  (Read 743 times)

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Offline rpetitho

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Rigol 1054Z user-error or oscilloscope problem?
« on: November 04, 2019, 06:51:24 am »
So I was doing some testing on a project and had a strange issue. Here are three photos of the response curve I was testing. All are the exact same curve with very different oscilloscope measurements. First photo was a single shot at 500mv resolution, second photo is the same shot zoomed out to 1v resolution, third is another shot of the same response at 1v resolution. Did I screw something up? Why do the last 2 photos look so different when they should look very similar? Let me know if you need more info.

[attach=4]
 

Online Fungus

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Re: Rigol 1054Z user-error or oscilloscope problem?
« Reply #1 on: November 04, 2019, 09:08:54 am »
Did I screw something up? Why do the last 2 photos look so different when they should look very similar? Let me know if you need more info.

I think what you're seeing is op-amp overload/recovery.

Your signal goes way off the top of the screen somewhere and is overloading the op-amp responsible for vertical scale. Anything that happens before it has chance to recover from that is undefined. Switching to a different vertical scale will change the op-amp gain setting (or maybe even use a completely different op-amp) so you see different results.

nb. This happens to all op-amps and all oscilloscopes.

https://www.google.com/search?q=op+amp+overload+recovery+time

 
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Offline JohnPen

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Re: Rigol 1054Z user-error or oscilloscope problem?
« Reply #2 on: November 04, 2019, 09:18:51 am »
I was just about to say the same thing but Fungus beat me to it.  The return edge on the original shot is the poor op-amp struggling to recover!
 

Offline rpetitho

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Re: Rigol 1054Z user-error or oscilloscope problem?
« Reply #3 on: November 04, 2019, 10:17:21 pm »
Always something new to learn. I think my project may be performing better than the oscilloscope would have me believe. Thanks!

-Bob
 

Online hgjdwx

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Re: Rigol 1054Z user-error or oscilloscope problem?
« Reply #4 on: November 05, 2019, 01:38:49 am »
« Last Edit: November 05, 2019, 01:40:33 am by hgjdwx »
 

Online Miti

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Re: Rigol 1054Z user-error or oscilloscope problem?
« Reply #5 on: November 05, 2019, 12:00:45 pm »
I think even in the second shot (third picture) you saturate the input. You should always keep the trace within the screen limits to trust what you see.
That big spark at power up was by design!
 

Online Fungus

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Re: Rigol 1054Z user-error or oscilloscope problem?
« Reply #6 on: November 05, 2019, 12:55:35 pm »
I think even in the second shot (third picture) you saturate the input. You should always keep the trace within the screen limits to trust what you see.

And if a detail is so small that you need to push the rest of the signal far enough off the screen to cause problems? That detail isn't important...
 


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