Rigol HDO1000 and HDO4000 12bit oscilloscopes launched in China

[Kleinstein]

The 1 M input open noise should be what is relevant when using a 10:1 probe. The 9 M and some 5 pf to the input should not have very much effect on the noise. So the open input case has some justification.
The noise with a shorted input would be more what matters for the 1:1 probe. For really noise sensitive measurements the 1:1 probe may be attractive depite the BW limitations.
The shorted input case is also less effect from noise of the 1 M resistance at low frequencies that may swamp the actual amplifier noise. The 1/f noise cross over in the curves about corresponds to the input RC time constant.

One should get the scaling from measuring a known signal in the same range, not just the clipping points.
Normally there should be a known scale factor for the data formats to make good use of them. If not in file or manual, one should make such a table.

The noise curve with the 20 MHz filter enabled suggests that at least some of the filtering is done digital: the role off is quite steep and there is a regular stop band ripple that is rare for an analog solution.
For the comparison of the RMS noise with the 20 MHz filter enables the type of filter can make a difference, as the noise BW is different from the -3dB BW.

How comes that the noise spectrum extends to beyound 125 MHz with the data at 250 Ms/s ?

[miro123]

Here is the noise spectrum using 250Msample files and assuming 10 div full scale. Looks very clean up to 200 MHz!
On 1 V/div (10V full scale) the white noise level is 240 nV/Hz^(1/2), I think that corresponds to almost 10 ENOB.

1. What is the sample rate?
2. Do you apply FFT for all 250Msamples or you use signal stacking tecniques
3. Do you apply any FFT window function -e.g. Hamming, Tukey, Blackman

[maxwell3e10]

Here is the open input spectrum, a little higher than Johnson noise on 1 mV/div scale but  could be explained by typical input amplifier current noise. It's not so clear where the extra noise on 1 V/div scale is coming from.

[nctnico]

It looks like it has a different amplifier path for 50 Ohm, giving lower noise at low frequency.
The ffts and plots are made with Matlab.
EDIT:
Actually, to be sure, was the scope input grounded externally when on 1 MOhm setting, Dave? Because it gives std=48 uV, instead of 19 uV. I think you mentioned in the video it does not make a difference when using on-screen rms measurements.

1M tests used an open input. If I used an external 50ohm termination then that's effectively the same as the 50 ohm mode, unless there is actually different paths for the 50ohm and 1M input which is usually not the case for scopes.

Not quite. From what I've seen it is about 50/50 up 1 GHz whether there is a shared or seperate path.

[Fungus]

...I think that corresponds to almost 10 ENOB.

It's certainly looking like Rigol has delivered the goods this time.

[maxwell3e10]

...I think that corresponds to almost 10 ENOB.

It's certainly looking like Rigol has delivered the goods this time.

Well, this is actually wrong, ENOB equations always mess me up! Full range 10Vpp sine wave has only 3.5V rms, so SNR=20*log(3.5/0.009)=52 dB. So ENOB=(52-1.76)/6.02=8.3 bits.

For comparison Lecroy HDO4024 has 3.4 mV rms noise on 1 V/div scale, compared with 9 mV for Rigol.
https://teledynelecroy.com/oscilloscope/hdo4000a-high-definition-oscilloscopes/hdo4024a

[Martin72]

Batronix have now listed the HDO4000:

https://www.batronix.com/shop/rigol/HDO4000.html

User manual:

https://www.batronix.com/files/Rigol/Oszilloskope/HDO4000/0908-HDO4000_UserGuide_EN.pdf

[Domitronic]

Batronix have now listed the HDO4000:

Interesting competitor to the Siglent. At least if you don't need digital channels or function generator.

Lets see if an "easy hack" will be available for one of them.

The battery option seems not to be ready yet. Neither in Daves unboxing nor in the accessories at Batronix.

[switchabl]

Well, this is actually wrong, ENOB equations always mess me up! Full range 10Vpp sine wave has only 3.5V rms, so SNR=20*log(3.5/0.009)=52 dB. So ENOB=(52-1.76)/6.02=8.3 bits.

It may be worth noting that ENOB is usually defined in terms of SINAD which also includes distortion though. Of course, this needs to be measured with a signal present.

I do not mean to imply that the calculation itself is not valid. But it cannot be readily compared with ENOB values found in manufacturers' datasheets (and maybe should be called something else).

[2N3055]

As I suspected, Ultra Acquire mode is simply segmented acquisition mode.
That, according to manual has many limits:
The UltraAcquire mode is not available when any of the following functions is enabled:
cursors, decoding, Search, Zoom, Pass/Fail test, waveform recording, power analysis,
reference waveform, XY. To switch to the UltraAcquire mode, please ensure that all of
those functions are disabled.

So with such segmented mode all you can do is to display nice graphs (there are several different display modes). That has very limited use.

Also there is no mention of Zone triggers..
They have sort of real segmented mode that they call Record mode (like in previous models). It is unclear what you can do with it.

It has very eclectic featureset that seems disconnected and like designed by committee. Let's hope that is because platform is so new they didn't finish it yet.

[Martin72]

Hello,

Maybe we can make a noise comparison between Rigol and Siglent 12 bit scope.

I got a 12bit siglent...
They were several settings mentioned on the side before, which settings should I use for compare?

[JeremyC]

The HDO4000 doesn’t have bode plot option, nor sin(x)/x
In my opinion the SDS2104X HD from Siglent is better choice than the HDO4204 and it's worth the $581 extra.
I’m sure that earlier, or later somebody will figure out how to hack the SDS2104X HD

[tv84]

somebody will figure out how to hack the SDS2104X HD

You mean the HDO4204, right? 

[Martin72]

In my opinion the SDS2104X HD from Siglent is better choice than the HDO4204 and it's worth the $581 extra.

In my opinion it´s too early to say which is the better choice.
Nevertheless, what I saw on Daves video doesn´t make me weeping in the cushion.
I very much welcome the fact that there is now a second affordable 12-bit scope, which will be a nice head-to-head race that will spur both to peak performance, for the favor of customers what features and polished software concerns.

[Fungus]

In my opinion it´s too early to say which is the better choice.
Nevertheless, what I saw on Daves video doesn´t make weeping in the cushion.

Wait 'til the sub-$1000 version of this 'scope arrives before you decide to weep or not.   

[JeremyC]

somebody will figure out how to hack the SDS2104X HD

You mean the HDO4204, right? 

No, I meant the Siglent…
Did anybody liberate the SDS2104X HD already?

[JeremyC]

In my opinion the SDS2104X HD from Siglent is better choice than the HDO4204 and it's worth the $581 extra.

In my opinion it´s too early to say which is the better choice.
Nevertheless, what I saw on Daves video doesn´t make weeping in the cushion.
I very much welcome the fact that there is now a second affordable 12-bit scope, which will be a nice head-to-head race that will spur both to peak performance, for the favor of customers what features and polished software concerns.

Yes, I agree with you.
I should say “in my case” because for me no bode plot is deal breaker.

[Martin72]

The new rigols didn´t got internal awgs, maybe that´s the reason why there is no bode plot implemented.
They should do it like siglent and allow external awgs for - A question of the software.
Therefore my statement what too early concerns.

[EEVblog]

The HDO4000 doesn’t have bode plot option, nor sin(x)/x

It's got Sinx/x, but you can't turn it off.

[tautech]

somebody will figure out how to hack the SDS2104X HD

You mean the HDO4204, right? 

No, I meant the Siglent…
Did anybody liberate the SDS2104X HD already?

Pretty darn sure the chap that posted these screenshots didn't shell out for a SDS2354X HD and then apply the $ $ 500 MHz BW license 
https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-12bit-(published-for-chinese-domestic-market-only)/msg4422598/#msg4422598

[Fungus]

It's got Sinx/x, but you can't turn it off.

Turning it off would produce a mathematically incorrect display.

[egonotto]

Hello,

Maybe we can make a noise comparison between Rigol and Siglent 12 bit scope.

I got a 12bit siglent...
They were several settings mentioned on the side before, which settings should I use for compare?

Hallo,

If I remember correctly, you have the SDS2104X HD.

We just have to consider the difference in bandwidth when assessing it.
(According to tautech's hint, perhaps 200 MHz bandwidth would also be possible?)

Maybe you should not use the first channel, because with my RTA4000 the display there also disturbs something.

All 8 measurements with 200 MSa memory and 2 GSa/s sampling rate

1 mV/div 50 Ohm maximum bandwidth (100 MHz or 200 MHz)
1 mV/div 50 Ohm 20 MHz bandwidth
1 mV/div 1 MOhm maximum bandwidth (100 MHz or 200 MHz) open input (deepl say open entrance)
1 mV/div 1 MOhm 20 MHz bandwidth open input

1 V/div 50 Ohm maximum bandwidth (100 MHz or 200 MHz)
1 V/div 50 Ohm 20 MHz bandwidth
1 V/div 1 MOhm maximum bandwidth (100 MHz or 200 MHz) open input
1 V/div 1 MOhm 20 MHz bandwidth open input

Thanks in advance.

Best regards
egonotto

[coppice]

It's got Sinx/x, but you can't turn it off.

Turning it off would produce a mathematically incorrect display.

A mathematically incorrect display is one where the claimed maths is not correctly implemented. If the maths is correctly implemented as claimed then any display is correct. Some are more useful than others, and some are useful for specific purposes, but they are all mathematically correct.

[Fungus]

It's got Sinx/x, but you can't turn it off.

Turning it off would produce a mathematically incorrect display.

A mathematically incorrect display is one where the claimed maths is not correctly implemented.

I meant a display where the signal isn't being represented using signal theory math.

(or, at least, the best approximation to it which can be done within the constraints of the device)

If you turn off sin(x)/x then what do you use to display the signal? Linear interpolation?

[JeremyC]

The HDO4000 doesn’t have bode plot option, nor sin(x)/x

It's got Sinx/x, but you can't turn it off.

Referring to the user guide this scope doesn’t have sin(x)/x interpolation and the display mode is vector only, to my knowledge it’s the same as in the MSO5000 scopes.
Check section 19.1, page 238 in the user guide.