Author Topic: Rigol ds1054z internal noise?  (Read 1074 times)

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Offline Mozee

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Rigol ds1054z internal noise?
« on: February 21, 2018, 04:28:05 am »
Hello there,
I need your help guys with the noise I’m getting as indicated in the attached video
I was playing with this little thing and I read that the noise should be zero when coupling is set to ground but as you can see in the attached video it is not! Also there is about 50Mhz frequency being indicated and I have no idea where it is coming from.

Is my scope normal? Could anyone test his rigol scope to reproduce this behavior? What’s normaland what is not?

Note that I am somehow new to oscilloscopes!

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Online Fungus

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Re: Rigol ds1054z internal noise?
« Reply #1 on: February 21, 2018, 04:39:28 am »
I was playing with this little thing and I read that the noise should be zero when coupling is set to ground but as you can see in the attached video it is not!

I don't know where you read that but it's not true on a DS1054Z.

 
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Offline frozenfrogz

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Re: Rigol ds1054z internal noise?
« Reply #2 on: February 21, 2018, 04:53:47 am »
It is the same on my unit.
Keep in mind though, that measurement takes place on screen and you have selected 10x probe, so all on screen values are measured times 10.
1x mode in the 1mV - 5mV range it measures around 300-500 uVpp.

Can not tell you where exactly that noise is generated - likely the ADC - but in my book the signal to noise ratio is pretty OK for a sub 400€ device :)
He’s like a trained ape. Without the training.
 
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Offline Mozee

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Re: Rigol ds1054z internal noise?
« Reply #3 on: February 21, 2018, 05:11:13 am »
So your unite has exactly the same behaviour? Same noise and frequency?
Also would by any chance affect it’s  ablity to correctly measuring waveformes?
Also is there any way to reduce this noise to zero or its about or actually should I?
 
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Offline frozenfrogz

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Re: Rigol ds1054z internal noise?
« Reply #4 on: February 21, 2018, 05:44:44 am »
Also is there any way to reduce this noise to zero or its about or actually should I?

Every scope will have some kind of background noise present. Reducing it to absolute zero does only work in a perfect world. If you really need that kind of precision for squiggly lines of very low voltage signals, be prepared to drop some serious amount of money on a differential preamplifier such as the Tektronix ADA400A plus maybe a scope with 12-bit ADC.

If that is the route you are wanting to go, head over to the m&ms (metrology maniacs, no offense! :-*). They can initiate you to the rites of hunting down noise!

If you simply want to see squiggly lines of your signal, don’t bother too much about it. Get to know your tool for what it can and can not do :)
He’s like a trained ape. Without the training.
 
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Offline Mozee

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Re: Rigol ds1054z internal noise?
« Reply #5 on: February 21, 2018, 05:52:27 am »
You made me laugh also made my day knowing that my scope acts normal  ;D ..
To be honest I just wanted to know if my little scope is normal or not and I need to know the limitation of it so where should I start?
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Online tautech

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Re: Rigol ds1054z internal noise?
« Reply #6 on: February 21, 2018, 06:29:03 am »
You made me laugh also made my day knowing that my scope acts normal  ;D ..
To be honest I just wanted to know if my little scope is normal or not and I need to know the limitation of it so where should I start?
Start by watching this:
https://www.eevblog.com/2014/04/10/eevblog-601-why-digital-oscilloscopes-appear-noisy/

Then Pt 2.
https://www.eevblog.com/2014/04/27/eevblog-610-why-digital-scopes-appear-noisy-part-2/
Avid Rabid Hobbyist
 
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Online Fungus

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Re: Rigol ds1054z internal noise?
« Reply #7 on: February 21, 2018, 07:01:41 am »
Also is there any way to reduce this noise to zero

The only way to reduce it is to live in a Faraday cage in a bunker with no electrical devices around. Even then it won't be zero.

or actually should I?

No, don't worry about it, it's normal.

(It should actually be a little bit less when you connect a probe).

Start by watching this:
https://www.eevblog.com/2014/04/10/eevblog-601-why-digital-oscilloscopes-appear-noisy/

Then Pt 2.
https://www.eevblog.com/2014/04/27/eevblog-610-why-digital-scopes-appear-noisy-part-2/

You forgot this:


 
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Offline MT

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Re: Rigol ds1054z internal noise?
« Reply #8 on: February 22, 2018, 02:03:18 am »
Hello there,
I need your help guys with the noise I’m getting as indicated in the attached video
I was playing with this little thing and I read that the noise should be zero when coupling is set to ground but as you can see in the attached video it is not! Also there is about 50Mhz frequency being indicated and I have no idea where it is coming from.
Is my scope normal? Could anyone test his rigol scope to reproduce this behavior? What’s normaland what is not?
Note that I am somehow new to oscilloscopes!

Why do you have one of the greatest electrostatic generating towels ever made on top of your scope?
Deliberately electrocuting all your bredboard setups?
 
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Offline imidis

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Re: Rigol ds1054z internal noise?
« Reply #9 on: February 22, 2018, 02:23:17 am »
Plastic bag too?
Gone for good
 
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Offline Mozee

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Re: Rigol ds1054z internal noise?
« Reply #10 on: February 22, 2018, 03:02:53 am »
Wow, never knew that this microfiber towel is an electrostatic charge generator! the plastic bag too!!
We always learn, till the moment we’re dying , we learn how it feels to be dead
 

Offline ogden

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Re: Rigol ds1054z internal noise?
« Reply #11 on: February 22, 2018, 03:51:28 am »
Could you re-do your test? - Disconnect all probes/cables except power cord, set probe to 1X and bring up measurements using "measure" button, obviously set measure source to channel you are looking at. Mine shows Vpp = around 300 uV, @ 5ns/div. Funny thing that at 5ms/div it shows around 480uVpp :) yet I still find this normal.
 

Offline rodcastler

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Re: Rigol ds1054z internal noise?
« Reply #12 on: March 07, 2018, 11:16:33 pm »
 Sometimes noise gets in through the mains. I have some LED strips to illuminate the bench I have to actually turn off in some measuring scenarios due to high freq interference coming from the power supply.
« Last Edit: March 07, 2018, 11:25:10 pm by rodcastler »
 

Offline Porcine Porcupine

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Re: Rigol ds1054z internal noise?
« Reply #13 on: March 08, 2018, 10:45:47 am »
Does anyone know what ground coupling on this oscilloscope does exactly?

I think on older oscilloscopes ground coupling physically disconnected the probe and connected the oscilloscope's input to ground using a switch you flipped or a relay. I don't hear a relay click when setting the DS1054Z to ground, so I assume it doesn't do that.

The manual says "When the coupling mode is "GND": the DC and AC components of the signal under test are both blocked."

Is it just filtering all frequencies? If that's the case, I'm not sure what use it would be. It wouldn't even allow you to check for an offset in the ADC.

By the way, some DSOs actually do just draw a line at zero volts when the coupling is set to ground:

https://www.tek.com/support/faqs/unlike-other-dsos-when-channel-coupling-set-ground-theres-perfectly-flat-baseline-ie-no
 


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