REVIEW - Owon SDS7102 - A look at the SDS series from Owon

[Sarasir]

Hi TomC,

it's good to know that they sell spare parts directly because you never know what will happen during tinkering around and it's also good practice once you've invested such a long time to make that thing usable to have backup parts in the shelf.

A common audio - and not just audio - setup is e.g. when checking/designing a filter or tone control that you connect the generator in parallel to scope CH I and to the input of the DUT, and to connect the output of the DUT to scope CH II. Then by sweeping the generator through you can see easily the frequency- and phase characteristics of your DUT. And you wouldn't use a probe to monitor the output of the generator, just a direct connection is what you need. It does not even need to be a BNC cable, any shielded one will do - provided your scope is clean!.

You know I already have concepts, pictures and ideas in the back of my head for after I'm done with the switchers. I guess there will be more noise comming up as rf-loop says. The display, of course is already on the list. But step by step.


---------------------------------------------------------------------------------------------------------------

Hi rf-loop,

thanks a lot, also for the paper! I will get to it soon.

It was very interesting, almost exciting to read your last post. Now we know a lot more about the history and current situation of the 'Owons'. It's a pity that they cannot open up to serious and advanced users and engineers who spend lots of time to make things good and also to help them. But beeing in this business for almost 50 years I know all kinds of 'blah-blah people' and especially in this business you meet quite a variety. (But I have to add that after I was working with companies like Rohde & Schwarz and Tektronix for many years, there you encounter many wonderfull and highly qualified people. Otherwise they could not keep up with their high standarts.)

And to the nylon spacer, even if I didn't know the history but the reason why it's put in is as I thought:  To reduce transferred noise fom the Z-plane to the input BNCs.

And to the trick on how to hunt the other noise with a 2 channel scope, I already did that a bit because I have seen already the hidden noise behind that I could not trigger to by just 'sensing' the little switchers around with a short wire loop or pig tail.

It's always wonderfull to get verification from other people that you are on the right way.

And to your last Btw I want to say that a scope is a long term investment and you never know what challenge or project will come up next.
It could be that suddenly you need a certain feature - like high input sensitivity - you never needed before. Only then you know or usually will find out whether your equippment is good enough or not.  As I'm quite experienced using scopes I did a basic over-all test before - but how many hobbyists are able to do that on their first scope - they are still studying. Or a small company needs a scope to do a certain test in production where non of the inherent problems appears.
In short, you can not say right after purchase if you will be entirely happy with a scope or a car or whatever highly sophisticated thing you bought. Most of the time and for most people it will take years to find out all pros and cons.

Btw, do you have a schematic of the input circuitry of the 9302 and could you pass it on to me?  I guess I might need it after beeing through with the switchers. I know I could retrace the PCB but you know, it will take many days rather weeks to do that.

[Sarasir]

Hi TomC,

...and I would like to ask you to think about this and tell me what comes up:

(scope on battery power)

Let's take it to an extreme and imagine that we would put the whole scope into a tight and close metal box. Then, do you think that there would be any noise on the metal box to be measured?
I would say no! (The cage of Faraday - nothing goes in and nothing goes out)

Then lets drill a hole into the box just as big as necessary for one input BNC and let's solder the BNC sleeve all around to the metal of the box. Do you think that there is noise on the BNC?
I would say no! (Because we cut the return path of the noise emission by means of the box.)

Then lets do a bigger cut-out for to be able to see the screen but cover it with a transparent and conducting mesh.

And in addition lets drill smalle holes for shafts and extensions either plastik or even better metal ones all grounded by springs so we can operate the buttons and knobs.

What would you think? Noise or no noise on the BNC?
Again I would say No noise!



And my conclusion would be that we just need to find a good compromise between the non shielded and the totaly shielded Owon scope. To minimize shielding to excatly the parts which needs it.  As a start e.g. we do certainly not need to shield the handle of the Owon you know.

Looking forward what you say....

[TomC]

Hi Sarasir,

Both Carrington and lemon tried painting the inside of the Owon's cabinet with a conductive coating to achieve a Faraday cage effect. However, they both later on decided to take it off. Primarily, because there was more visible GND noise with the coating than without it. Personally, I thought it was a good idea to shield the cabinet that way, primarily because it would make the scope a little more immune to outside interference. But as I see it, the problem inside the scope was different, I believe the radiated emissions from the switchers were bouncing off the coating and landing on places that were not being affected originally, and this resulted in more visible GND noise. I think if you try something like this the results will be different since you are shielding each switcher individually. 

On the thing about the test setup with the scope and DUT in parallel. If I understand correctly this is designed to minimize phase delays introduced by a scope probe so you can accurately compare the phase at the DUT's input and output. But if that's right, wouldn't using the same type of probe at both the input and the output accomplish the same thing? Without thinking about it too much, it seems to me that although there would be phase delays, they would be basically equal, and you could still make valid comparisons. I'm probably missing something!

At one time I wanted to use transparent shielding on the screen, but as I searched around for a source, I couldn't find small pieces at a reasonable price. So I sort of gave up on that idea. Maybe you have better luck.

[Sarasir]

Hi TomC,

coating does not work of course. I would never have tried this. You know it's not just the volume resistivity (reziprocal: specific conductance) but also the problem of how to connect it properly. The BNCs would be the correct point and it would need some matall foil and clamps on the BNCs and what else... You use coating e.g. to avoid or keep out statics or it would help in audio shielding but very little for HF. Why do you think HF shields in professional machines are anodized with silver. Remember the skin effect!

Of course you could also work with probes but to patch the generators output directly to the scope is the easiest way. And don't forget the trigger. Why do you think all professional generators have an extra trigger output? It's because then connecting the trigger out to the external trigger in of the scope you are free to change the output to whatever level you need without having to readjust the trigger. They stay always in perfect sync. Remember, if you change the level of a sine wave the trigger point will move in time if you had adjusted it off zero what often is necessary for several reasons. Or it would stop triggering if you turn down the output of the generator below the trigger level chosen. So the professional way is to trigger externally in our example setup. Of course you could also do the trigger connection with a probe, but, come on.... should I continue?

And, phase delays through cables are not a basic problem in audio equippment, only when the circuit starts oscillating erratically usual at high frequencies.

Probes have a resistive and a capacitive attenuator that compensates for phase delay - ideally. In practise there might be a little present at the upper bandwidth limit but if that's much you should calibrate your probe or it's junk.

My setup was only hypothetical for to get a better imagination of the circumstances and a clear picture in mind how these probs could be solved. And I do not think that I will need a mesh eventually.

[TomC]

Hi Sarasir,

The idea for the coating, as I remember, came from the way some other manufacturer finishes the inside of the cabinet of their scopes, I think it may have been a Tek DSO. Not sure what the material was, but for the DIY I think Carrington used copper based and lemon nickel based. Didn't know about the use of anodized silver on shields, but as you said, it would certainly improve the conductivity at high frequencies right where is needed (the skin), learn something new every day...

Like I said in my post, I wasn't thinking too much when I wrote about phase delays. So of course I agree that this shouldn't matter much for audio work, propagation time wouldn't exceed more than a few ns at worst. I'm more used to using probes, hardly ever take them off the scope, so I was just curios why they were not the preferred connection method in this setup.

As for the hypothetical setup of your previous post (the faraday cage with holes connected to the BNC), I still think it's an extension of the chassis, so any common mode currents flowing through the chassis will also be present throughout the part of it that is used as a faraday cage. Of course, currents tend to follow the path of least resistance, so the same intensity is not felt in every corner, but I believe there will be electrons in motion everywhere on this surface.

[rf-loop]

About something.

Faraday box is not easy for higher frequencies in this kind of situation. If build whole Owon including its mechanic new and so on... situation is very different.

Inside Owon appears frequencies over 200-300MHz (fast parts of rising edges in some SMPS)

It is good to imagine that  50mm  long and 10mm diameter copper rod is "50 ohm" for around 350MHz sinewave.  You can use it as 50ohm termination and your transmitter output do not short circuit at all but it just see around 50ohm normal load. With 3GHz or more it is much more fun.

If you make "faraday box".  between every point of box is also reactance.  Oh well, then think that there do not flow currents over this plate. It is true for DC if you have faraday box what is connected just using exacly one point. But more high freq we go and then inside box shielded machine have "lot of" capacitive connections to this faraday box different positions.

This very simple thinking may continue to deeper and deeper and it can easy think that doing some kind of conductive painting inside Owon box do not help in practice just nothing and there is lot of reasons.   Or take just 1mm copper plate. say example 10cmx10cm.   
What is inductance between its opposite corners. Try calculate its reactance for example 500MHz.
I can ask, is it easy to make faraday box in practice so that you still have GND connection to some point(s) and pot of capacitive (and also inductive) connections to this box infinite points. And between any point there is inductance and capacitance.  (it is good to remember that with these situations in owon example this Z-plate is not "one GND". (You can measure different RF between every point of this plate. And also from separate PCB's separate points of GND's. Whole construction is "mugpie".

Yes fraday box for LF is more easy and faraday where is not connections from inside to outside.
And then, there is magnetic fields... 
But small local SMPS noise can attenuate more easy to acceptable level (what is acceptable level?) if do these locally with hard work with many mechanical/electric modifications.

Do not produce noise. It is much better than make noise and then try isolate/attenuate noise from travel to wrong place.

[Sarasir]

rf-loop,

my idea with the cage of faraday was only for to develop further imagination and feeling for what to do. You know, getting a clear picture of what are the extremes.

I can underline all what you say. Of course there is reactance in the cage everywhere but I think with very low Q and btw. what's about the eddy currents?

My way is of course according to your proposal to remove and shield all switchers in small tin boxes to kill the noise right there where its originated, and I'm almost done with that. Only the -7.4V switcher on the main psu is still waiting but for now I have this connected through long wires to the scope and of course additional filter components.

My experience so far is that the moment I close a tin box with a running switcher inside the measurable spikes outside go down to almost zero. But I also have used additional capacitors and coils to filter down the spikes on the in- and outputs.

(it is good to remember that with these situations in owon example this Z-plate is not "one GND". (You can measure different RF between every point of this plate. And also from separate PCB's separate points of GND's. Whole construction is "mugpie".

Yes, I discovered that as well - see earlier posts.

TomC,

coating is of course a practical way to further improve shielding as done in some low cost Tek machines. But not to be enough here where very strong emission is the problem. Here you would have to at least anodize the plastik. E.g. the inside of the plastic covers of the Tek P6046 differential probe is gold plated.

Please once more think about if you want and tell me your opinion of how does the return path of the noise that is present on the BNC input sleeves look like.
(That is what's going around in my head in anticipation of what to do against the remaining noise once the switcher noise has been eliminated and the cage of Faraday model was just one try or approach to get the whole picture.)

If there is current comming out somwhere there must be a path through which the loop closes, no doubt (I think that it must take place through the electrical field that's build up towards the evironment by all other parts of the Owon except the BNCs themselves once they are connected to another machine like a generator.)

...and I found the emty 5 literes tin can I have kept after having used up the Greek olive oil that was inside. Unfortunately the Owon is a little bit too high to fit in right away. But - I know myself - as soon as I have the Owon working again I will bend and torture this poor can to get the Owon inside.
Then we will see.....

[TomC]

Sarasir,

There is no single return path in my mind, and I doubt that the BNC sleeves themselves are at the center of any particular current flow path. But there are currents flowing through the Z-plate and all the ground planes connected to it. These elements are in theory a common path, but to individual current loops they are just part of the roadway that comprises the loop. For DC and low frequency loops I view these elements as part of a wider highway with a fairly even traffic distribution that accommodates the needs of multiple loops. However, at higher frequencies, because of impedance variations due to interconnections and/or structural characteristics, the traffic distribution is no longer even. As a result the electron traffic will be more intense in the areas offering a lower impedance path, and of course less intense in those areas with a higher impedance. Nevertheless, every part of this highway will be affected by this traffic to one degree or another. The BNC sleeves are connected to it, so they are part of the highway, although as I said, I doubt that they are at the center of any particular path.

Of course, most of the traffic is comprised of differential currents used to power the various scope circuits. But some of this traffic, particularly HF traffic, are common mode currents that originated with the switchers due to stray capacitances, inductances, or radiation. Although unintended, these are also current loops, and are also what we call GND noise. Had these currents been confined within the boundaries of the switchers that originated them, by proper design, circuit layout, and/or shielding (like rf-loop says, don't cause noise), they wouldn't be an issue. As it stands, this didn't happen originally, and although it has been alleviated on current production, it hasn't been eliminated. There is probably little incentive to do so since competing products suffer from similar ailments of various degrees.

Now, however, I think that what you are doing can potentially confine the fast rising currents associated with each switcher to their respective boundaries. Basically, it seems to me that this is a major redesign. With the switchers isolated any common mode currents attempting to escape via the associated input or output wires can be effectively filtered with a common mode choke. Along with some additional differential mode filtering, I think these switchers can potentially be as clean as traditional linear circuits. With that accomplished the HF common mode currents on the Z-plate and ground planes should be virtually gone. At that point, in my view, the only impediment to a totally GND noise free scope will be the TFT. I'm not sure that a Faraday cage that doesn't include the screen can eradicate the effect of this noise source. However, from what I've experienced, this noise source is mostly near field, and usually can be easily avoided by keeping the probe cables away from it. So if it's not too bothersome, why mess wit it!

[Sarasir]

Hi TomC,

a fine and profound overview of the situation, thanks a lot!

Just one step further I would like to push you if you don't mind:

(Not considering any local details like switchers or display. Just let's assume that the only thing we know is that there is lots of noise and a common DC ground plane everything connects to (would not be even necessary but it helps) with all that 'hasty and speedy social life of countless electrons and many of them quite ambitious in there urge to escape to other realms', like you described in a more scientific way.)


And this then would be my question:

May we not choose any point of this complex system and say, here we would like to have a point of zero potential towards the outside world and what would we have to do to make that a reality?

[TomC]

Hi Sarasir,

I don't think you can make it absolutely zero potential under any circumstances, but you can come close by providing a better earth ground than the one it already has. If we are going to go to the edge of the deep end, I think we would be thinking of a massive, with plenty of conductive surface to cover high frequencies, rod driven deep into the ground. Something large enough will probably exhibit very little deviation from zero potential even if struck directly by lightning. I don't think this is the solution you are hoping for, but what else could you do without straying into science fiction?

[Sarasir]

Hi TomC,

brute force you meen! Unfortunately a bit too much to realize and live with in this case I would say...

I thought it should be possible to establish a point of zero by closing the loop(s).
That meens to bring back all the electrons which want to escape exactly to the point that you want to be 'zero'. That means in practice to catch all 'run-away' electrons with a shield and connect that shielt to that point. This point then should be in a way satisfied and free of potential.

Through our correspondence every time the picture in my head gets a bit more in focus.

The whole thing acts like a balance I think. The more electrones are escaping (and also returning) on one side the more electrones will be pushed out and pulled in on the other side - the BNCs - because the whole system needs equilibrium.

I'm almost at a point where I can see the whole thing pretty clean without even removing the switchers but then the shield must be very good, and perhaps even more important the connection of the shield to the point of zero.

Have my 'externalized' power supply(s) tested and ready now. Tomorrow I will connect it with the main circuit through about 80cm long wires I prepared today.


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Correction to my drawings!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

When checking through my papers today I found a failure in my drawings of the Power Scheme (Original and Modified) and of the +5.6V switcher:

The +5.6V switcher is not enabled by the +3.3V switcher's output!  It's Enable input is connected to the +8.4V of the main PSU (which supplies also it's input)!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Correction to my drawings!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[TomC]

Hi Sarasir,

I also agree with the concept of confining/closing the loops within a controllable environment. Which is I what I think you are doing with your external power source. There is one element that I don't see in your drawings that I believe would help considerably getting the noose even tighter, common mode chokes. To me these are like miracle devices, because the inductance is mostly apparent in the presence of common mode currents, but practically disappears from the point of view of differential mode currents. I would consider using these on the wires connecting the external power source to the Owon. You could even try ferrites on the wire bundle, which are roughly equivalent to hardwired common mode chokes, and if they make a difference then go the hardwired route.

Leaving the switchers in situs, in my opinion, would leave few and probably insufficient options to control the environment to the extent that you are striving for, because to a large extent you have to live with what Owon has already done. So the possibilities for changing the layout and adding components are severely limited.

Anyway, I wish you the best of luck in your upcoming experiment, and I'll be waiting to hear the details of how it turned out!

[Sarasir]

Hi TomC,
to exernalize all switchers is not directly part of closing the big loop(s) to the input BNCs I may remark. It just will make that easier by taking away the contribution of these switchers to the big loop, therefor keeping down the shielding efford. (of course if you put a switcher into a tin box it's also closing a loop, but just locally!).

And to the cores: If you look at my pics again you might see a big core near the main PSU through which the colered wires - the ones from the PSU to the scope - go. Bu that is preliminary still.

There are also draw backs using cores. (And btw. my drawings also are just preliminary and I have not drawn common mode cores yet because I'm not sure yet if, how and where to put them exactly)
You may easily use a core on a two wire connection (signal and return path like your probes) but if you have a bunch of wires with different currents and different noise occurencies all referred to a common ground wire you might have to consider that a core acts also as a transformer (not to speak about core material and saturation effects yet.). That meens that you might couple spikes from one voltage line to another and vice versa. All might be cancelled out again as long as the sum of all electrones goes back through the common ground wire that also goes through the core, but first tests I made showed that in practice it is not exactly like that.
So better concentrate on that later, but now as you mentioned it there is already a picture getting sharper and we will certainly find out more about.

Yes, of course and I repeat what you have said in other words, once having them out they will go back only after having them all caged in a propper tin box.

Well, and thanks for the good spirit. Soon we will know a bit more.

 

[TomC]

Hi Sarasir,

Yes, I think you got it pretty well covered for now, and will know more once you test it. I attached a partial schematic of the SDS input that I think came from tinhead some time ago. Don't know if you had already seen it or if it also applies to the 9302. But I remember you asked rf-loop for something like that and I just ran into it while rummaging through my SDS7102 folders. Once again, good luck!


Edit:
The PDF has better image quality.

[TomC]

I recently decided to purchase an inexpensive pair (under US 50) of 200MHz probes to take advantage of my SDS7102's surplus bandwidth. Browsing through eBay, Amazon, and others I found a number of choices in this price range. From a pair of Neewer EM#01 for US 15.60 (free shipping) to a pair Of Owon T5200 from a website in Austria for Euro 29 (+shipping & other fees). I finally decided to order a pair of Li Hua P6200 from a US eBay seller for US 33.90 (free shipping). These probes are advertised as high quality suitable for HP & Tektronix, and feature lower input capacitance than the other contenders in this price range.

Once the shipment arrived I proceeded to test their bandwidth by scoping different signal sources and comparing the results with some of the other probes I own. The attachments show some of the comparison results. In all of these captures CH2 (yellow trace) is connected to the Li Hua P6200, while CH1 (red trace) is connected to either a Hantek PP-80 (60MHz) or to an Owon T5100 (100MHZ). The last 3 images show the specs for these probes as they appear in their respective user manuals. All probes were carefully compensated prior to these tests.

#1a through #1b - Here I compare the response of the 60MHz Hantek prove (H) and the 200MHz Li Hua prove (L) at different RF generator settings. The amplitude of the signals is very similar, so additional testing is needed to find out whether the Hantek probe is quite a bit better than 60MHz or if the Li Hua is no better than 60MHz.

#2a through #2b - Here I compare the response of the 100MHz Owon probe (O) and the 200MHz Li Hua prove (L) at different RF generator settings. At 50MHz the amplitude of the signals is very similar, but after passing the 60MHz mark the amplitude of the signal displayed by the Li Hua probe is quite a bit less than the amplitude displayed by the Owon probe.

I repeated this test using a Tektronix P6105 (100MHz) and obtained almost identical results. I also tested the second Li Hua probe to rule out the possibility of a single defective probe. The results were identical, so at this point there is little doubt in my mind that my new 200MHz probes are really misrepresented 60MHz probes.

#3a through #3b - Here I compare the probes using a fast rise signal (< 4ns). The probes are connected to the scope calibrator's output via a T and two BNC to probe tip adapters. The Owon probe clearly outperforms the Li Hua with a 2ns advantage. The Hantek and Li Hua probes have almost identical rise time, with the Hantek winning by a fraction of a ns. It seems that the Li Hua probe barely qualifies as a 60MHz probe.

I explained to the eBay seller, AST Labs, that although these probes were misrepresented, I didn't want to return them because I planned to post my findings here and needed them as proof of my claims. The seller responded quickly and indicated that they were unaware of this problem and would investigate immediately. They also offered me a full refund without requiring the return of the probes.

There is a number of possible reasons why these probes don't perform as labeled and all I can do is speculate. The probes in my possession look and feel genuine, and the label looks identical to the one in the attached image. So I doubt that they are counterfeit or fake. It's possible that these are really P6060 probes that got inadvertently mislabeled at the factory. On the other hand, it's also possible that someone is trying to make a quick buck by relabeling less expensive P6060's and hoping no one will be able to tell the difference. However, I have no reason to believe or suspect that the seller, AST Labs, is involved in any type of fraudulent behavior. They have a stellar reputation with 100% positive feedback and handled this case quickly and without hesitation to my satisfaction.

I'm still interested in a pair of inexpensive 200MHz probes, but at least for now, decided to stay away from Li Hua for obvious reasons. So I ordered a pair of Hantek PP-200 probes from an Amazon seller for US 31.99 (free shipping). I'll be reporting my findings as soon as I get them.

[Sarasir]

Hi TomC ++,

have the Owon working again but there is still some tweaking to do. There is ringing on the wires, and absolutely awkward, there is new noise in my appartement. Heavy noise I've never seen before. I guess that somebody around me must have purchased a new TV set or so (Soccer Worldcup just started). My whole place is polluted with around 2MHz noise comming through the mains supply but also through the air. Toutching the input of my Tek 475A the noise level is even higher then the 230V/50Hz mains voltage displayed. The Owon is of course not switched on and the new noise shows like packets of HF synchronous to the 50Hz so it's not a DC/DC converter but rather a AC/DC type whatever. Have no Idea. Looks a bit like a Thyristor or TRIAC dimmer but with continous oscillation over about have of the sine period starting allways around zero transition.
I called the German Bundesnetzagentur (Federal Network Agency) who is controlling and enforcing all respective regulations but have to call again on Monday for to speak to a technician.

What else to say for now. I don't know yet what I will do. Building myself a big cage of Faraday or to wallpaper my workshop with aluminum foil...
Perhaps the Bundesnetzagentur will come and do some measurements and tell my neighbours to bring back their new TV set or throw away their broken microwave oven. It's just crazy, but time will tell...

[TomC]

Hi Sarasir,

Good to hear from you!

I was wondering what happened! I'm glad that the Owon is working again!

Over here the FCC deals with situations like that, once in a while a HAM radio operator causes trouble for me, but it never lasts long enough for me to report it.

[Sarasir]

....and before checked again and it has disappeared - discovered it two days ago and yesterday it was still present. Now it's again just 50Hz sine wave without any HF noise just the usual abberations. Strange.... hope it doesn't come again.

[mohandes]

hi
i live in Iran and i want buy scope but i can pay 360-400 Euro .(or little more price)
i want buy GDS-1072-AU or SDS7102E and i need your help .
when marmad say SDS7102 better i see the price a little much for me so i see marmad in this forum to tell us to buy Rigol DS2072 / DS2000 series DSO , so i am amazed to buy which of them.
i need 70 or 100MGH dig scope , if you have another choose please say me.
so GDS or Owon or Rigol ? can tell me more data please

[TomC]

Hi mohandes,

I own an Owon SDS7102, for the price, even with a few shortcomings, I think it's a good value and you get 100MHz, is usable to about 200MHz, and has a large LCD. On the other hand, the Rigol DS2072, is a better scope, with a built in upgrade path when you need it, but it's only 70MHz, at least initially, and you have to pay almost twice as much. So it's a matter of what you can afford and what you foresee you'll need in the future. At least that's my opinion. Good luck!

[mohandes]

thanks
what is your idea about GDS1072AU ?
what is diff between Owon SDS7102 and Owon SDS7102E ??
and DS2072A ,DS2072A-S ??
i need good scope , but i dont know which is the best !!
1 GSa/s for sampling is good for me too and between 60 to 100MHZ, i need your data for best scope that you have.
excuse for my English

[TomC]

Hi mohandes,

Here are a couple links with more information on the GDS1072AU and DS2072A-S. From what I see the A-S includes a built in signal generator:

https://www.eevblog.com/forum/testgear/new-instek-scope-gds-1072a-u/

https://www.eevblog.com/forum/testgear/any-rigol-ds2072a-s-user/

The SDS7102s have an alpha designator that tells you some of the features limitations. Mine is an SDS7102V, which has a VGA interface for direct connection to a computer monitor. It also has a battery option and deep memory is standard. From what I can see the SDS7102E is a less expensive model that doesn't have the VGA or battery option, and the deep memory is an extra cost option.

[mohandes]

Hi mohandes,

Here are a couple links with more information on the GDS1072AU and DS2072A-S. From what I see the A-S includes a built in signal generator:

https://www.eevblog.com/forum/testgear/new-instek-scope-gds-1072a-u/

https://www.eevblog.com/forum/testgear/any-rigol-ds2072a-s-user/

The SDS7102s have an alpha designator that tells you some of the features limitations. Mine is an SDS7102V, which has a VGA interface for direct connection to a computer monitor. It also has a battery option and deep memory is standard. From what I can see the SDS7102E is a less expensive model that doesn't have the VGA or battery option, and the deep memory is an extra cost option.

thanks
can you put here for me like of your scope ?
Mr marmad said DS2072 better than SDS7102 , do you agree whit him ?
your scope have good in all frequency and bandwidth ?
regards
se this topic please
https://www.eevblog.com/forum/testgear/which-model-of-scope/

[TomC]

In many ways it is, but it all depends on what do you mean by better? For example: How much are you willing to spend? And what features are important to you? There is no black and white better or worst!

[mohandes]

In many ways it is, but it all depends on what do you mean by better? For example: How much are you willing to spend? And what features are important to you? There is no black and white better or worst!

for same pay ( i can pay 800$ to 850$)  i want buy the best , i say need 70 to 100MHZ and 1 to 2Gs for sampling.
and i want know which is better for same cost ?
thanks again
i read datasheet of SDS2000(SDS2072 ) and DS2000A(DS2072 ) , and i think SDS better .
SDS7102 good too for me .
and i really Helpless .
regards