Rigol DHO804 Test and Compare Thread

[Mechatrommer]

Some of that grass will be spurious tones from ADC nonlinearities, and some are folded back signal that was aliased.

same rule applied to any FFT calculating machine, siglent, rigol, tek, hp R&S whatever. is at the mercy of sampling HW system. to get rid aliasing entirely, you need brickwall filter, and that is a theoritical filter one cant achieve in real world. unless you are far crippling the sampling mechanism with uch uch lower BW filter.

Stop being rude and aggressive. I explained something, replying to his "math junk" comment to which I disagree. I didn't say it was "Rigol problem".
Of course every system has same. There are no ideal systems. We discussed this many times.
At his point I don't have any opinion on how well it performs. Thanks to your data I will take a look and then will comment.

and i'm also providing information relating to that. whether you already know it or not. i'm not being rude nor i say i disagree, infact i do agree i'm just adding fact to it. sorry if you got insulted too much

Otherwise known as "artifacts".
While studying physics at the University of Chicago, I had friends in the archaeology department who thought artifacts were a good thing (as opposed to rocks carved by natural processes).

yes and every systems are not perfect, they have their own artifacts.

[iMo]

When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor

[Fungus]

You don't understand much do you?

Aaaaand.... we're done here.

[2N3055]

You don't understand much do you?

Aaaaand.... we're done here.

Thank you!!

[TimFox]

Otherwise known as "artifacts".
While studying physics at the University of Chicago, I had friends in the archaeology department who thought artifacts were a good thing (as opposed to rocks carved by natural processes).

Usually called spurious tones in SA world... When in spectrum mode I call them so.. Seems appropriate..

Yes, spurious tones are a good example of artifacts in a system.
My professor at U Chicago was from Italy, and objected to my use of an incorrect Latin term "spuriae" for the plural of spurious for a system with multiple artifacts.
(Spuriae is a real word, meaning the feathers of the bastard wing of a bird.)

[Mechatrommer]

When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor

why play with theoritical signal that never existed? here FFT from computer generated sin wave (saved in CSV)... -280dB noise floor the -160dB harmonics are probably Double (64bits) FP precision artifacts (or Single 32bits? cant remember).

[2N3055]

When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor

why play with theoritical signal that never existed? here FFT from computer generated sin wave... -280dB noise floor the -160dB harmonics are probably Double (64bits) FP precision artifacts.

Well, it would be interesting to quantize that sinewave to 16 bit and 12 bit level and then push those through FFT.......... Simulations are not useless if targeted.

[ebastler]

[Dirac pulse...]
why play with theoritical signal that never existed? here FFT from computer generated sin wave...

Spot the contradiction! 

[Mechatrommer]

When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor

why play with theoritical signal that never existed? here FFT from computer generated sin wave... -280dB noise floor the -160dB harmonics are probably Double (64bits) FP precision artifacts.

Well, it would be interesting to quantize that sinewave to 16 bit and 12 bit level and then push those through FFT.......... Simulations are not useless if targeted.

that need some work. but should be better than what i've shown from real 12bit DSO....

[2N3055]

When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor

why play with theoritical signal that never existed? here FFT from computer generated sin wave... -280dB noise floor the -160dB harmonics are probably Double (64bits) FP precision artifacts.

Well, it would be interesting to quantize that sinewave to 16 bit and 12 bit level and then push those through FFT.......... Simulations are not useless if targeted.

that need some work. but should be better than what i've shown from real 12bit DSO....

Certainly. But it would show theoretical numbers to have baseline...

[Mechatrommer]

[Dirac pulse...]
why play with theoritical signal that never existed? here FFT from computer generated sin wave...

Spot the contradiction! 

right! new information. so what does it tells? dont feed it a pulse? what happen if we feed it to a real SA? will it see something?

edit: for fun i added dirac 100Vpp, not sure what use of this other than theoritical... so far the lesson is dont send SA a pulse, esp FFT

edit: and dirac 300uVpp, the eyeball noise from DHO800... -120dB floor...

[tautech]

What is your link to Siglent? It does seem to go beyond "generally liking their products".

Most folks watching this forum got it by now.

But you don't feel comfortable disclosing it when asked, let alone in your profile info? Well, you will have your reasons. But please be aware that it affects the reception of your posts once readers have realized that you have a hidden agenda or loyalty here.

the only valid question would be: have I posted wrong facts anywhere? Or in this thread particularly?

It's not about posting wrong facts, but about posting selectively picked facts which make "your" product look good, and glossing over aspects where the competing product has advantages. That's what decent salesmen do, and it is certainly what tautech and you have been doing here.

You could of course research members posts and particularly their topics to seen how they fit into this forum.

AFAIK there are only a few resellers here, a couple each from the US and EU and myself from deep south in the Pacific.
Some have tried and represented many brands and due to their technical expertise only focussed on brands that fully meet their specs.

Beta testers are many more and from all parts and have extensive experience in the TE world and outstanding knowledge otherwise they would not be accepted as beta testers.
Clues to whom a few are is in their participation in various threads before equipment came to market.

Those that can be bothered to do the research can easy discover these members that for whatever reason chose to fly below the radar rather than be attacked for brand preferences.

[ebastler]

AFAIK there are only a few resellers here [...]
Beta testers are many more [...]

It does not matter to me whether someone is making money from customers by selling Siglent products, or is getting money and/or free stuff from Siglent directly. If the result is that they feel loyal to Siglent, and hence don't give balanced advice here but act as Siglent advocates, that's what I need to know and what I refer to as salesman behavior.

You could of course research members posts and particularly their topics to seen how they fit into this forum. [...]

As a side note, one does not have to actually read the posts. It is sufficient to observe who's thanking whom on a regular basis to identify the members of the "Siglent mutual back-patting society". 

Those that can be bothered to do the research can easy discover these members that for whatever reason chose to fly below the radar rather than be attacked for brand preferences.

Why would it be more desirable to be perceived as someone with a brand preference (and a material interest) who is not upfront about it?

[Fungus]

As a side note, one does not have to actually read the posts. It is sufficient to observe who's thanking whom on a regular basis to identify the members of the "Siglent mutual back-patting society". 

Also the fact that they're posting about Siglents in every single Rigol thread.

[2N3055]

AFAIK there are only a few resellers here [...]
Beta testers are many more [...]

It does not matter to me whether someone is making money from customers by selling Siglent products, or is getting money and/or free stuff from Siglent directly. If the result is that they feel loyal to Siglent, and hence don't give balanced advice here but act as Siglent advocates, that's what I need to know and what I refer to as salesman behavior.

You could of course research members posts and particularly their topics to seen how they fit into this forum. [...]

As a side note, one does not have to actually read the posts. It is sufficient to observe who's thanking whom on a regular basis to identify the members of the "Siglent mutual back-patting society". 

Those that can be bothered to do the research can easy discover these members that for whatever reason chose to fly below the radar rather than be attacked for brand preferences.

Why would it be more desirable to be perceived as someone with a brand preference (and a material interest) who is not upfront about it?

All of that is a moot point.
Problem is not who works for who or do they wear it on forehead.
Problem is staying on topic and dealing with facts.

For instance, I publicly say I prefer Siglent scopes because until now, trying all kinds of scopes, I prefer LeCroy type analytic scopes and Siglent makes something similar and is clearly more affordable. And they have excellent quality, and are decent company. I was Rigol user first, and I gave up. I was very interested in DS7000 at the time and eventually gave up, for instance. I also think Siglent is way better in bug fixes, adding features. Evidence is all there.

So yeah I'm biased towards Siglent because their "way" is closer to way I think.

Martin tried to make a comparison thread between cheaper SDS1104X-E and bit more expensive DHO800. They are in similar price bracket of entry level "not a toy" scopes, where DHO800 is sort of a "new generation DS1000Z".
And Rigol marketing and fanboys started victory lap of "game changers" etc etc.

But if you do cold fact based analysis it is not so clear cut. Especially because Rigol made spectacularly horrible release of what are basically release candidate products. Software for whole series was released in alpha stage, DHO900 violates Nyquist if not run in special combinations of channels/MSO etc...

So Martin being a scope person, buys a DHO800 (with his own money ) out of sheer curiosity. He also have access to dozen of other scopes (Siglents and LeCroys) so he can compare it.
And all we get is, well, you saw what we get..

In this topic it was not any of "Siglent fanboy club" that sabotaged the effort.

If I was not persistent, there would not be any good information about:

- segmented mode an its usage with measurements and decoding (note THERE IS NOT a word about it in manual. According to Rigol that is not possible)
- Details of statistics
- Some FFT data pulled from scope that circumvents closed and nontransparent "trust us there is a bump here" FFT on scope.

Martin also showed
- decoding in a table,
- statistics in a table,
- how you can arrange windows in all kinds of ways not only vertically (also not something you could learn from any Rigols docs).

All of that actually puts DHO800 in more positive light, better than what could be gleaned by looking at their own marketing and docs.

And all of that effort by "Siglent fanboy club" was actively disrupted by people who actually have DHO800.

Animosity and hate even if you say good things.

Which does not matter but facts. 

[iMo]

Rigol is rather small company based on to me available info (530 FTEs and several subsidiaries w/ perhaps S&M only). Their product range is not small for that amount of core FTEs, however. Based on my own experience with 100xFTEs larger players (and w/ the actual number of knowledgeable doers related to a specific product) the number of R&D people dedicated to a single product series (like the 800/900) must be miniscule, imho. Like 2.5 FTEs max (1 sw, 1.5 hw) directly assigned to the product series till the product launch, with some shared support of course. There could be another small cross-team for their ASICs. They may have some small testing teams, perhaps abroad in their subsidiaries, but the bottleneck is their home staffing, imho. I can imagine myself there is a single person sitting in their office these days, reading these threads (and emails from their subsidiaries), laughing, and slowly debugging the sw issues of the 800/900/1000/4000 series in a pace the working hours allow

[ebastler]

Problem is not who works for who or do they wear it on forehead.
Problem is staying on topic and dealing with facts.

I partially agree.

Some users here generally like Siglent products, but nevertheless take a balanced approach -- Martin and you are prime examples in my mind. Some others have a strong tendency to advocate for Siglent, rub in "pro Siglent" facts which are unrelated to the discussion at hand, dismiss Rigol design aspects in unobjective and insolent ways etc. Those are the ones I have referred to as "salesmen"  -- no need to name them here.

And there are a few users who push back. In contrast to the "Siglent circle", they don't seem to be affiliated with Rigol in any way, beyond having bought some equipment with their own money. I don't recall seeing them attacking Siglent in threads about Siglent TE, only pushing back against the undercurrent of Siglent advocates in the Rigol-related threads. And yes, sometimes their tone gets out of hand and becomes insolent as well.

I don't know why there is this imbalance of Siglent vs. no Rigol representatives on the forum. Maybe Rigol generally works with larger, multi-brand distributors, so none of those has been as motivated and committed to advocate for Rigol and use the forum to build a group of beta testers? But it is obvious that the imbalance exists. We can't force it to disappear, so the next best thing in my mind would be transparency -- which is why I would encourage people to disclose their ties to Siglent (and other brands), as e.g. tautech does.

[In the interest of transparency: I consider myself a brand-neutral hobbyist. I own (budget) equipment from Rigol, Siglent and a couple of other brands, and some old stuff from Philips and Hitachi, all bought with my own money.]

[tautech]

We can't force it to disappear, so the next best thing in my mind would be transparency -- which is why I would encourage people to disclose their ties to Siglent (and other brands), as e.g. tautech does.

Some link their website and that should be enough IMO.

[Fungus]

You don't understand much do you?

Aaaaand.... we're done here.

Thank you!!

Bottom  line: The Rigol can do everything.

You want sliding window? It does it.

You want to manually reset every time? Set the window size to 10000000 and it's the same thing.

[2N3055]

Problem is not who works for who or do they wear it on forehead.
Problem is staying on topic and dealing with facts.

I partially agree.

Some users here generally like Siglent products, but nevertheless take a balanced approach -- Martin and you are prime examples in my mind. Some others have a strong tendency to advocate for Siglent, rub in "pro Siglent" facts which are unrelated to the discussion at hand, dismiss Rigol design aspects in unobjective and insolent ways etc. Those are the ones I have referred to as "salesmen"  -- no need to name them here.

And there are a few users who push back. In contrast to the "Siglent circle", they don't seem to be affiliated with Rigol in any way, beyond having bought some equipment with their own money. I don't recall seeing them attacking Siglent in threads about Siglent TE, only pushing back against the undercurrent of Siglent advocates in the Rigol-related threads. And yes, sometimes their tone gets out of hand and becomes insolent as well.

There will be those that that are overzealous.
And I could name few Rigolites(TM) (fans of Rigol ) that were dropping in any discussion and when Siglent was mentioned they would simply just smash the party..  For instance whenever you mention that Siglent has always running segments (triggered capture memory) so you can always stop scope and go back if you wanted to, they would start attacking how that is stupid and useless. Because their favourite brand does not have it. Or when Siglent released 12 bit scope then it was all the rage how 12 bit is not important and that is just a elitistic bulshit to push expensive scopes. Then suddenly apparently 12 bit is all important. By same people. While now and then, 12 bit, like anything else, is important if you have use for it. If not you could be equally well served by 8 bit scope.. etc etc. And Rigol is here and reads it all..

And then you have users like Performa01. I understand him well. Like me, he sees all the nonsense and deflection being said. Like me he knows what is important in a scope. More BW is always better, unless you need low noise at low frequency, when suddenly more BW is your enemy. More memory is always better though. Lower noise is always better. More measurements is always better.

Many fresh, new, digital scope users think history started yesterday. While in fact it has been decades. There are many thing that are universal truth proven many times and then you have people that insist that "resetting stats is not needed, and if you set statistical sample to 4 on sliding windows stat that is all you need.. Ar you hyping reset because your Siglent has it?".... Hell yeah it has it, like ALL other 7 scopes I have... And than insist that I should prove that I'm right.. Because they reject "Argument from authority". While that is simply screaming ego that cannot admit they don't know something, combined with Kruger-Dunning and unhealthy ambition to win at any cost, including dirty play. If they don't like what I say, that is not because they are lacking knowledge (of any type and form required), no it is because I am .... Choose any type of derogative....
Worst thing is, not knowing something is not shameful. Not at all. Corpus of human knowledge is so wast, even full blown geniuses have fraction of a fraction of a fraction of knowledge in any given topic.

And since both Performa and myself are not spring chickens, with years you get weary of the noise....
Which shapes responses, tone, and how much you are ready to explain why.
I do it to the best of my abilities.
And when I'm wrong I own it.

Mind you this is not some apologetic statement or complaint or attack of any sort towards anybody.
It is just a heart to heart in our honest exchange here to explain a bit how I feel in all this.
I don't get paid for any of this. I like helping people when I can. It's nice to be nice.
I make recommendation that I genuinely think will benefit asking party.
Based on my experience. So I will preferentially suggest something that Siglent has that I tried and it is proven to work well.
Or I will (and had) recommend Keysight, Picoscope, Micsig and Rigol..

[2N3055]

You don't understand much do you?

Aaaaand.... we're done here.

Thank you!!

Bottom  line: The Rigol can do everything.

You want sliding window? It does it.

You want to manually reset every time? Set the window size to 10000000 and it's the same thing.

Yes, after Spanish inquisition torture treatment, you finally verified for us that does have it. I gave it a passing grade.

The comment is about 20 posts from you how that is not important, that is unnecessary, how I'm this and that,  instead of one simple yes for benefit of all.
And make note, not a single time I questioned you to show me any proof of it. I took your word for it.
You said you looked and confirmed it was there, was enough confirmation for me.

For all of the questions I asked there was a reason (hint: not Siglent related): these are important functions and in ALL of current Rigol documentation there is no explanation or even mention of it. There is some mention of how stats can be reset but not how and where and no image.
So images and answers you posted clarify that, and since they were positive, they actually benefit Rigol
And thanks to you now, potential buyers have better quality info, what it can and cannot do.
That would be even more important if those functions were not there.
It is shame it took so much effort from an "enemy" to enable you to be good an helpful and benefit Rigol community.
I must be worst Siglent fan ever....

Ruminate on that.

P.S. If we have to go all in in name calling, I would not be offended if called "Siglent compatible"....

[Fungus]

There is some mention of how stats can be reset but not how and where and no image.

I searched for the word "reset" in the manual and got this as the first hit:


This is the second hit:


If you go to section 11.2.2 you get this:

[Fungus]

This is the menu that pops up when you touch a measurement on the side bar:

You can reset the statistics for that measurement, enable an on-screen indicator (the orange lines above/below the signal when you're looking at Vpp), remove it, or go to the full measurement settings.

So... just two taps to reset the stats for any measurement.



If you open the full measurement settings you see this popup wher you can configure all sorts of things. See the manual for details:

[Fungus]

Edit, I just noticed another way to reset the stats!

This is for all the people who hate touch screens and don't want to dedicate the "Quick" button to resetting stats:

When you press "SINGLE" it resets the stats and captures a single event (it shows count=1 in the stats display).

Now you can press "RUN" and it continues counting up from 1.

Two button presses = stats reset. 

[Fungus]

I'm trying to figure out if my cheapo 150Mhz probes will keep me below Nyquist if I enable all 4 channels with 250Mhz bandwidth enabled. I just poked the probe into the BNC of my SigGen to see what I got.

This is my rise time with the crocodile clip:


nb. The four pink lines aren't cursors, they're the overlay you get if you turn on the indicator for rise time.

This is my rise time with the little spring accessory:


There's quite a big difference between the two!

Conclusions...

Crocodile clip: 163MHz=a tiny bit over.
Spring: 196MHz = nope.