Author Topic: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope  (Read 109655 times)

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Offline David Hess

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #900 on: January 03, 2020, 02:06:15 pm »
Having a look in the specs of the supply, it claims that ripple will be under 1mVrms.

I would be really cagey about a modern DSO's automatic RMS measurement.  Some measure AC RMS and some measure AC+DC RMS and the terminology is not consistent.  Dave even did a video on the subject.

Quote
And the rigol just can´t display it, it´s own noise will cover this, regardless of any filter attempts. ( Ripple of a simple supply is no problem, it´s "big enough" to display it)

Oscilloscopes tend to be pretty noisy.  Sometimes an external low noise amplifier designed for the measurement bandwidth is required to make power supply noise and ripple measurements.

Older oscilloscopes going back to the 1970s often had bandwidth limits lower than 20 MHz to limit noise sufficiently for their most sensitive range.  So the more sensitive or noisy the oscilloscope was, the lower the bandwidth limit was to produce a reasonable display.
 
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Offline Martin72

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #901 on: January 03, 2020, 02:12:01 pm »
Hi again,

Quote
offset comes from waveform not being symetrical so it has DC component when it gets averaged (integrated) on coupling capacitor.

Test it out what happen to the signal displaying when it´s not symmetrical and scope is ac-coupled, see pics below. (No averaging mode, doesn´t take a effect when using it)
Further I´ve noticed a little offset (last pic), where I don´t know whre it´s coming, from the build-in Generator or from the scope itself.

Martin



Offline Fungus

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #902 on: January 03, 2020, 09:04:06 pm »
I have to put that into perspective….
Having a look in the specs of the supply, it claims that ripple will be under 1mVrms.
And the rigol just can´t display it, it´s own noise will cover this, regardless of any filter attempts.

Ok, so there's basically no ripple.  :-+

(try increasing the load on the power supply until some appears....)
 

Offline Martin72

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #903 on: January 03, 2020, 09:37:21 pm »
Yes and it´s remarkable, because it´s a really cheap supply.
A little annoying, but I don´t pay attention on other scopes in the last years, whether they would show the same behaviour like the rigol on AC-coupling, see pics.




Offline Fungus

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #904 on: January 03, 2020, 11:20:53 pm »
Yes and it´s remarkable, because it´s a really cheap supply.

It will have ripple, it's just a question of load.

A little annoying, but I don´t pay attention on other scopes in the last years, whether they would show the same behaviour like the rigol on AC-coupling, see pics.

I hope so. The whole point of AC coupling is that the low frequency components of the signal decay towards the center. 30Hz isn't fast...

 

Offline Martin72

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #905 on: January 03, 2020, 11:32:28 pm »
Quote
it's just a question of load.

Measurements were taken at 2.5A load, maximum load was 3A...
(I use a cooking plate, no joke…)


Offline Fungus

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #906 on: January 04, 2020, 07:29:56 pm »
Quote
it's just a question of load.

Measurements were taken at 2.5A load, maximum load was 3A...
(I use a cooking plate, no joke…)

It might have a massive amount of capacitance on the output, but that's generally regarded as a bad thing in a PSU.

 

Offline Clint

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #907 on: January 25, 2020, 02:26:41 pm »
Anyone seen any UK deals on these I am going to order a 5074 this week and join the fun :)
=-=-=-=-=-=-=-=-=
g33K5 L1k3 80085
 

Offline cruse123

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #908 on: January 30, 2020, 01:53:28 pm »
Excuse me, has anyone tried the XY mode in this oscilloscope?

I have ordered an MSO5074 a few days ago and am now happily playing around with it. It seems that the line in XY mode is too thick. Use BNC cables to directly connect waveform generator outputs to oscilloscope inputs, resulting in a very thick circle. Even if couple modes of two channels are both set to GND, there is still a pretty large square in the center of the canvas. Tried different time base and high-res mode, but no big improvements.

I have used several models of oscilloscope, but none of them show such a thick pattern, even the lower models of Rigol. Is there any advice on settings? Thanks in advance!

917650-0917654-1
 

Online TK

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #909 on: January 30, 2020, 03:28:37 pm »
Your vertical setting is at 100mV/div and it looks like the thick trace is due to the high noise floor of this scope
 

Offline fact

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #910 on: January 30, 2020, 05:08:53 pm »
My MSO7000 shows exactly the same behaviour even at large input signals and low sensitivity settings. I hope Rigol addresses the problem in a future firmware update like they improved the beam width in normal mode in the last update.
 

Offline Martin72

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Re: EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope
« Reply #911 on: January 30, 2020, 05:26:36 pm »
Quote
I hope Rigol addresses the problem in a future firmware update

Ah, hope, rigol, firmware update....This wouln´t go together  >:D
Joking, "End of january" say wrote me once - Now, they have one day left... ;)
 
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