MSO vs MDO - What's going on?

[starlite4321]

Hello.  I'm just starting to consider buying my first modern oscilloscope.  I've read all the definitions I can find.  Based on that, I would have guessed that MDO's were basically MSO's plus a dedicated RF channel providing higher performance spectrum analysis capabilities than MSO's (for example:https://www.tek.com/landing-page/mixed-domain-oscilloscope).  That would make MDO's more "advanced" than MSOs and presumably more expensive.  But Tektronix has a Series 3 MDO and a more expensive (more advanced?) Series 4 MSO.  And yet more expensive Series 5's and 6's that are also listed as MSO's.  Is what's going on that Tektronix's higher end MSO's are so capable that they can do the "MDO job" as well as an MDO from each of their "regular" inputs but since they don't have a dedicated "RF Input", they're still called MSO's?  Thanks in advance for any clarification!

[EEVblog]

The RF spectrum analyser part of that scope has about $50 worth of parts in it, tops.
The 4, 5, and 6 series scopes have much more expensive higher bandwidth front ends and other options that make them more expensive that a "relatively low end" 3 series MSO + MDO RF front end.

[starlite4321]

Thanks - appreciate the response!  But what I am struggling with is more the use of the terms "MSO" and "MDO", and I was only using the Tektronix models as an example.  I see similar confusion with other manufacturers too.  In particular, are the more expensive MSO's doing the whole job that the MDO's are doing on each of those inputs?

[EEVblog]

Thanks - appreciate the response!  But what I am struggling with is more the use of the terms "MSO" and "MDO", and I was only using the Tektronix models as an example.  I see similar confusion with other manufacturers too.  In particular, are the more expensive MSO's doing the whole job that the MDO's are doing on each of those inputs?

Tek is the only one that makes an "MDO" scope, it's pretty much a niche product in the mid range scope category. This is why Tek's new higher end 4/5/6 Series scopes don't have MDO capability, because it's a niche thing that never really caught on in mainstream scopes.

In theory the other higher end scopes are not doing the same job an MDO is, because they don't have proper RF front ends.
But all scopes are capable of doing FFT to give you a spectrum analyser display. What performance they have depends upon the price and capabilities of the individual scope. e.g. Bandwidth, sample rate, 10/12 bit converter etc. It gets more complicated when you start talking cross-domain triggering etc, so it not an easy black and white answer.
A really high end non-MDO scope will beat the pants off a cheap(er) MDO scope, unless you need to measure really low level RF signals, then you'd need an external RF amplifier on the non-MDO scope.

[starlite4321]

Great, thanks!  That answered it.  In short you're saying something along the lines of, "low end scopes have low end (or no) RF capability, mid end scopes might have some RF capability, Tek created a category that pushed improved RF capability at the mid end and called it "MDO" but it didn't catch on in the industry, and higher end stuff is better at everything including RF capability than mid end stuff no matter what it's called (everything else being equal).  That makes sense - thanks very much!

[EEVblog]

Great, thanks!  That answered it.  In short you're saying something along the lines of, "low end scopes have low end (or no) RF capability, mid end scopes might have some RF capability, Tek created a category that pushed improved RF capability at the mid end and called it "MDO" but it didn't catch on in the industry, and higher end stuff is better at everything including RF capability than mid end stuff no matter what it's called (everything else being equal).  That makes sense - thanks very much!

Yep, basically.
Que the MDO fanboys...

Also, the new Series 3 MDO is essentially just the old MDO3000 hardware model with the pretty new "Series" user interface and bigger screen tacked on.
Basically, when Tek designed their new industry leading Series 4/5/6 series scopes they decided not to include MDO capability. I guess that shows how much they value that MDO capability, and/or how successful it was in the industry. Would be very interesting to know their reasoning.

[starlite4321]

Ok, I've gotta ask you ... I think I'm noticing that everything Tektronix makes is more expensive than roughly corresponding stuff by other manufacturers, including optional s/w.  My experience has been pretty much you get what you pay for.  Is that the case here - bite the bullet and shell out the dough (you'll understand why it cost that much after you've used it for awhile) - or are they just charging for their name?

[Howardlong]

I agree, the real power of an MDO that supports time and frequency correlation is very niche: even as a mixed signal RF guy, I find it is a very rarely used feature.

Note that the MDO3000, although it includes the RF spectrum analyser, does _not_ perform the time and frequency domain correlation like the MDO4000 does. The MDO3000 operates either a scope or an SA, but not both at the same time. The MDO4000(b/c) is the only scope I'm aware of that will do the SA/Scope correlation.

It's not clear to me yet whether or not the new Tek 3 Series MDO does this correlation, I haven't seen any evidence that the 3 Series is anything other than an MDO3000 with a big telly and a touch screen UI.

With my RF hat on, unlike the MDO, I've yet to see a traditional scope FFT that's much practical use for RF purposes.

Edit: FWIW, my bench scopes in regular use are: Tek MDO3054, Tek MDO4054C, Keysight MSOX3054A and Keysight MSO7104B. By far the most used one is the MSO7104B, the oldest scope in technical terms.

[EEVblog]

Ok, I've gotta ask you ... I think I'm noticing that everything Tektronix makes is more expensive than roughly corresponding stuff by other manufacturers, including optional s/w.  My experience has been pretty much you get what you pay for.  Is that the case here - bite the bullet and shell out the dough (you'll understand why it cost that much after you've used it for awhile) - or are they just charging for their name?

Can of worms opened!

If I was paying my own money I would not be buying a Tek.
Tek make great mid to high end gear, no doubt, but they really don't have their head around the "bang-per-buck" market.
I think you'd be hard pressed to find many on this forum that would recommend the Tek as a general purpose scopes. For years that have been known for a lack of innovation (MDO excluded) and slow old designed at a premium price.

I'll move this thread to the test equipment forum where it will be more eyeballs.

[Mr. Scram]

Ok, I've gotta ask you ... I think I'm noticing that everything Tektronix makes is more expensive than roughly corresponding stuff by other manufacturers, including optional s/w.  My experience has been pretty much you get what you pay for.  Is that the case here - bite the bullet and shell out the dough (you'll understand why it cost that much after you've used it for awhile) - or are they just charging for their name?

They're charging for their name. Tektronix was the way ahead of the competition in the CRO era, but has been lagging a bit since. They still have an excellent reputation but I don't think they're doing any better than R&S or Keysight. They've been doing some pretty nifty things recently, I have to admit.

[starlite4321]

Again, thanks for all the comments.  Very very helpful.  I know this is a totally subjective question but, I'm finding myself drawn to the Tek 4-Series MSO although the pain-of-cost is excruciating (especially after you add the "Spectrum View" software which isn't included until you get to the 5-Series version).  I'm retired now but I remember a problem my team worked once forever that would have taken about 10 minutes to figure out with that, "Visual Trigger" and time coincident data info.  Not to mention the large, hi-res screen and lots of parallel inputs.  Can you suggest a more cost effective alternative?

[nctnico]

In this price bracket you should definitely take a look at R&S RTM3000 series (or even a step up). These at least have a 10bit ADC and also have a spectrum analysis mode.

If you are serious about buying then I suggest to get a Keysight, R&S and Tektronix scope on loan and just try them all before deciding to buy one. They all use 3000/4000 to identify a certain price / features bracket. If you buy a car you take it for a test drive first. Why should an expensive oscilloscope be any different?

[tautech]

Can you suggest a more cost effective alternative?

BW requirements ?

[2N3055]

I agree, the real power of an MDO that supports time and frequency correlation is very niche: even as a mixed signal RF guy, I find it is a very rarely used feature.

Note that the MDO3000, although it includes the RF spectrum analyser, does _not_ perform the time and frequency domain correlation like the MDO4000 does. The MDO3000 operates either a scope or an SA, but not both at the same time. The MDO4000(b/c) is the only scope I'm aware of that will do the SA/Scope correlation.

It's not clear to me yet whether or not the new Tek 3 Series MDO does this correlation, I haven't seen any evidence that the 3 Series is anything other than an MDO3000 with a big telly and a touch screen UI.

With my RF hat on, unlike the MDO, I've yet to see a traditional scope FFT that's much practical use for RF purposes.

Edit: FWIW, my bench scopes in regular use are: Tek MDO3054, Tek MDO4054C, Keysight MSOX3054A and Keysight MSO7104B. By far the most used one is the MSO7104B, the oldest scope in technical terms.

I worked on the telemetry node that had analog, digital and RF module.  To be able to trigger on incoming RF packet and then observe timing and decode digital packet, and see analog out changes was useful for me at that time. I managed to use RF demodulator probe for RF trigger and did everything else on MSO scope.  Also Keysight 3000T (and many other like Lecroy) have gated FFT, so I also managed to see some stuff in reverse: I triggered on RF module output and set long pretrigger time, so I was able to see rough RF spectrum right before digital event...
Unfortunately SH BB60C that I use to take a look at the modulation, doesn't have Trig out... Stupid.

MDO made some of that very easy and quick..
MDO is very nice idea in my opinion. I was kinda hoping other would adopt it and improve on it, instead, even Tek dropped it. It's a shame.

Closest thing to it now is to get some real time SA with trigger out (Rigol RSA3000/5000 for instance) and use it to trigger on RF events and use MSO scope Trig in.
On that you could also use IF output to look at the downconverted signal if you need that...

But still, not the same convenience..

Two scope brands that have something similar are R&S (very nice spectrogram mode, up to 1GHz scope, spectrum  to 1.25 GHz ), and GW Instek MDO series (200MHz scope, 500MHz SA mode max).  But AFAIK, they cannot trigger on RF event, which was kind of MDO4000 killer feature.

[starlite4321]

Thanks for the reply!  Yeah, definitely agree about trying the top contenders in the trade out before investing.  Still, I remember never really knowing WHAT I'm going to need until the s--- hit the fan.  It's a bit of a guessing game.

As for BW, I'm guessing 200 mHz will do at least as a start.

Oddly, R&S's website says they don't distribute their Spectrum Analysis package for the RTM3000 (and presumably any other scopes) in NA which is where I am.  Also, it doesn't seem to have a version of "visual Trigger" which is high on the list after seeing it demonstrated on the Keysight 4000X and the Tek 4-Series.

This is going to be a long slog...

[EEVblog]

If you are serious about buying then I suggest to get a Keysight, R&S and Tektronix scope on loan and just try them all before deciding to buy one. They all use 3000/4000 to identify a certain price / features bracket. If you buy a car you take it for a test drive first. Why should an expensive oscilloscope be any different?

Yes, in this price you wouldn't spend your own money without trying.
And this a big purchase for someone in their retirement. What are your spec requirements exactly and we can help you.

[Howardlong]

Are there any independent reviews of the Series 3 and Series 4 yet?

In particular, I'm interested in how responsive and usable the UI is: these usability facets have long been a negative aspect of Tek DSOs, even though on paper Tek can appear to be competitive from a feature perspective.

I strongly recommend that you find the opportunity to have a quality hands-on experience before making the purchase.

[EEVblog]

MDO is very nice idea in my opinion. I was kinda hoping other would adopt it and improve on it, instead, even Tek dropped it. It's a shame.

Yes, I was quite stunned when the 5 series came out and didn't have it.
Like I said, the parts cost very little, even if the spectrum analyser part isn't as good as a "real" SA.

[EEVblog]

Oddly, R&S's website says they don't distribute their Spectrum Analysis package for the RTM3000 (and presumably any other scopes) in NA which is where I am.  Also, it doesn't seem to have a version of "visual Trigger" which is high on the list after seeing it demonstrated on the Keysight 4000X and the Tek 4-Series.

It's called "zone triggering" and the RTM3000 has it too. And yes, it's a real handy feature on modern touch screen scopes.
Almost any scope will be better value than the Tek.
Look for bundle specials, R&S have some at present:
https://www.tequipment.net/Rohde-and-Schwarz-promotions-and-offers/

Keysight have good deals on certified refurbished scopes:
http://www.ebaystores.com/keysight/

[tautech]

This is going to be a long slog...

Not so much really, list your must haves and then like to have and so on.
Just those alone can narrow down the contenders pretty quickly.

As yet we have 200 MHz
Display, size, touch ?
Sampling rate ?
Mem depth ?
MSO ?
Decode ?
and so on...........

[starlite4321]

Yeah, there's no substitute for actually using something.  There are always good and bad things that only surface that way.  As for independent reviews of the 3 and 4 series, I haven't found any yet but there's a good one on the 5-series by "The Signal Path".  There's a lot of stuff in it that would apply to at least the 4-Series too.  The guy loves it.

As for my requirements, they're vague and a little proprietary.  I have a partner who asked me to help with some design, fab and test for some research he's doing.  It's in the early stages so there's no way to tell what's going to come up over time.  I'd like to avoid the, "... boy I wish I'd thought about this and that ..." thing as much as possible.  And also the, "... it sure seemed like too much money at the time but I'd give my eye teeth to be able to go back and make that purchase again ..." thing.  I guess I'd like to find a best case general purpose scope minimizing the possibility I ignored something that turned out to be important. Like anybody. Of course I can always rent something if it comes to that.

Ok, well I'm glad I found EEVblog.  Thanks for the help everybody.  I'll check back again later.

[tautech]

Have a hunt through Dave's scope videos:
https://www.youtube.com/user/EEVblog

[starlite4321]

Hi tautech, thanks for the response.  Apparently we were typing at the same time.  As I said, things are a little to vague now to cover all the things you listed.  I'm going to count on upgradability for some of the ones you listed.  I can say I'd like as big a display as possible.  Room isn't as much a problem as old eyes are.  I like touch screens so that for sure and I'm sold on MSO - as I mentioned, that wasn't even a wet dream when I was a pup and it sure would have helped with some big problems.  The other things are "how much can you afford" things that don't have hard requirements.  At least not yet.

I'm definitely detecting a feeling that the Tek stuff isn't a good value compared with the alternatives from the people with recent (compared to me) experience on the blog here.  That's very valuable insight.  Right now the next on my list would be something along the lines of the Keysight 4000 series.  Like everyone says, I'm going to have to get hands-on to decide.

Again, thanks to everyone for the advice!

[tautech]

Don't discount the B brands as they have a lot to offer for the $ to the point where you might buy 2 B brand units and cover all you'd need in a scope and RF for just the price of a high spec A brand scope, especially if fully optioned.

Best advice is to have a good look around and fire any questions at us thick and fast ! 


Oh and something else this forum can help you with:
https://www.eevblog.com/forum/testgear/equipment-discounts-from-saelig/

[Mr. Scram]

Hi tautech, thanks for the response.  Apparently we were typing at the same time.  As I said, things are a little to vague now to cover all the things you listed.  I'm going to count on upgradability for some of the ones you listed.  I can say I'd like as big a display as possible.  Room isn't as much a problem as old eyes are.  I like touch screens so that for sure and I'm sold on MSO - as I mentioned, that wasn't even a wet dream when I was a pup and it sure would have helped with some big problems.  The other things are "how much can you afford" things that don't have hard requirements.  At least not yet.

I'm definitely detecting a feeling that the Tek stuff isn't a good value compared with the alternatives from the people with recent (compared to me) experience on the blog here.  That's very valuable insight.  Right now the next on my list would be something along the lines of the Keysight 4000 series.  Like everyone says, I'm going to have to get hands-on to decide.

Again, thanks to everyone for the advice!

Note that the Keysight 4000 series and 3000T series are largely the same oscilloscope under the skin. People have called the 4000 series the "Cadillac version". All Keysights up to and possibly beyond the 6000X series are based on the same Megazoom IV ASIC, although various series unlock more of the features than others. What all models share and Keysight's claim to fame is a very responsive interface. Pretty much everything is done in hardware on the ASIC and it shows. The oscilloscopes don't slow down as you enable more features and controls are snappy. Contrary to pretty much all competitors the claimed waveform update rate actually translates to real life, allowing more convenient troubleshooting of occasional events. The downside is that many key specifications are predetermined as that is what the MegaZoom IV ASIC has to offer. The screen resolution isn't as high as it is with some of the more recent oscilloscopes and sample memory is limited. That's not going to change without a new ASIC being released. The responsive behaviour and waveform updates are years later still best in class, though. Keysight has made an effort to keep their models competitive by enabling more options for free so you get more oscilloscope for your dollar nowadays. It may or may not interest you to know that a lot of options and a fair few cases bandwidth can be software unlocked and there are unofficial ways of doing this available.

Information on the current R&S offerings is a little more sparse but what I've seen is definitely impressive. They seem to be very well thought out machines made by people who actually sat in front of them and tested what works and what doesn't. If I had a healthy amount of money to spend I'd definitely take a good hard look at the 2K, 3K or 4K series. Considering your 200 MHz with room to upgrade requirement it'd have to be the 3K or 4K series. The mentioned R&S offerings are known for their 10 bit ADC's and deep memory depth, which almost seem to target the weaker areas of the Keysight offerings. Rather than speed accuracy seems to be emphasized. The interface responsiveness seems to be more limited, though the large touch screen and the use of "apps" provides flexibility and customization. Apparently the FFT capabilities are rather decent, but there too information is sparse. No alternative unlocking of these devices appear to be available, so any upgrades will need to be paid for.

[Howardlong]

Yeah, there's no substitute for actually using something.  There are always good and bad things that only surface that way.  As for independent reviews of the 3 and 4 series, I haven't found any yet but there's a good one on the 5-series by "The Signal Path".  There's a lot of stuff in it that would apply to at least the 4-Series too.  The guy loves it.

I have a lot of respect for Shahriar, he certainly knows his stuff, but be aware he was pretty wild about how good the MDO4000B & MDO4000C are too, and they have a frankly terrible user experience in terms of responsiveness and random operational choices apparently dreamt up by a team of monkeys with a dart board***. In his videos you'll hear the odd crumb of negativity, but that tends to be drowned out because understandably bearing in mind his solid technical expertise and experience, he concentrates on the hard technical features rather than the soft user experience. I'm not suggesting he's being disingenuous, far from it, his content is always invaluable, it's just that I find that the user experience is a very key facet of test equipment if you're intending to use the scope throughout the day, as opposed to sporadic or infrequent use.

***: Here are some examples of the bad UX on the MDO3000 and MDO4000. There are two rather than one multi-function knob, and sometimes you use the knobs, but sometimes you use the buttons to change choices, and with little apparent coherency, the confusion inhibits your natural workflow. Furthermore, I find myself continually fighting with (a) the acquisition settings, (b) the delay and expansion point, and (c) the pan control. Even after a few years' use of the MDO3000, I still find it a PITA to use. The MDO4000 exhibits an identical experience. If you compare it to a Keysight Infiniivsion scope, you'll know exactly what I mean, and it's why an old MSO7104B remains my go to scope on the bench despite the other available options.

[EEVblog]

Information on the current R&S offerings is a little more sparse but what I've seen is definitely impressive. They seem to be very well thought out machines made by people who actually sat in front of them and tested what works and what doesn't. If I had a healthy amount of money to spend I'd definitely take a good hard look at the 2K, 3K or 4K series. Considering your 200 MHz with room to upgrade requirement it'd have to be the 3K or 4K series. The mentioned R&S offerings are known for their 10 bit ADC's and deep memory depth, which almost seem to target the weaker areas of the Keysight offerings. Rather than speed accuracy seems to be emphasized. The interface responsiveness seems to be more limited, though the large touch screen and the use of "apps" provides flexibility and customization. Apparently the FFT capabilities are rather decent, but there too information is sparse. No alternative unlocking of these devices appear to be available, so any upgrades will need to be paid for.

I've got a video coming out tomorrow comparing various scopes on a rather obscure trigger mode capability. It just re-affirmed my opinion that the Keysight is best "daily driver" scope, it's just so fast and easy to use. Amazing little features enabled by the ASIC that other scopes just can't match. But a bit crippled these days in memory depth and screen realestate. The R&S has a bigger and more feature rich UI and better converter. And Siglent beats Rigol these days in bang-per-buck and performance in the lesser brand category, but neither really has any innovative features the big names don't. The big players like Keysight, R&S, Tek and Lecroy all tend to have some unique features others don't.
There is never any clear winner I'm afraid, it's horses for courses.

[EEVblog]

I have a lot of respect for Shahriar, he certainly knows his stuff, but be aware he was pretty wild about how good the MDO4000B & MDO4000C are too, and they have a frankly terrible user experience in terms of responsiveness and random operational choices apparently dreamt up by a team of monkeys with a dart board***. In his videos you'll hear the odd crumb of negativity, but that tends to be drowned out because understandably bearing in mind his solid technical expertise and experience, he concentrates on the hard technical features rather than the soft user experience. I'm not suggesting he's being disingenuous, far from it, his content is always invaluable, it's just that I find that the user experience is a very key facet of test equipment if you're intending to use the scope throughout the day, as opposed to sporadic or infrequent use.

***: Here are some examples of the bad UX on the MDO3000 and MDO4000. There are two rather than one multi-function knob, and sometimes you use the knobs, but sometimes you use the buttons to change choices, and with little apparent coherency, the confusion inhibits your natural workflow. Furthermore, I find myself continually fighting with (a) the acquisition settings, (b) the delay and expansion point, and (c) the pan control. Even after a few years' use of the MDO3000, I still find it a PITA to use. The MDO4000 exhibits an identical experience. If you compare it to a Keysight Infiniivsion scope, you'll know exactly what I mean, and it's why an old MSO7104B remains my go to scope on the bench despite the other available options.

Yes, the MDO3000 is horrible to use, and I said so in my various videos using it over the years. Tektronix shunned me as a result  But almost everyone who's used it says the same thing.

Likewise for the Keysight, they got practically everything on that right and is my preferred daily driver, and most people seem to agree.

This is me bumbling around with a series 5 on a trade show stand, I haven't used it enough to have an opinion, but seems way too big and complicated for a daily driver. it's the scope you bring out when you have some big requirement.

[Mr. Scram]

I've got a video coming out tomorrow comparing various scopes on a rather obscure trigger mode capability. It just re-affirmed my opinion that the Keysight is best "daily driver" scope, it's just so fast and easy to use. Amazing little features enabled by the ASIC that other scopes just can't match. But a bit crippled these days in memory depth and screen realestate. The R&S has a bigger and more feature rich UI and better converter. And Siglent beats Rigol these days in bang-per-buck and performance in the lesser brand category, but neither really has any innovative features the big names don't. The big players like Keysight, R&S, Tek and Lecroy all tend to have some unique features others don't.
There is never any clear winner I'm afraid, it's horses for courses.

That sounds like an interesting video! I'm surprised no other manufacturers seem to pursue a similar ASIC route even though they actually do roll their own ASICs. Rigol has just done one but achieved pretty much the opposite with a very sluggish MSO5000. It may be cheap but it's certainly not hardware accelerated to any similar degree.

[2N3055]

I've got a video coming out tomorrow comparing various scopes on a rather obscure trigger mode capability. It just re-affirmed my opinion that the Keysight is best "daily driver" scope, it's just so fast and easy to use. Amazing little features enabled by the ASIC that other scopes just can't match. But a bit crippled these days in memory depth and screen realestate. The R&S has a bigger and more feature rich UI and better converter. And Siglent beats Rigol these days in bang-per-buck and performance in the lesser brand category, but neither really has any innovative features the big names don't. The big players like Keysight, R&S, Tek and Lecroy all tend to have some unique features others don't.
There is never any clear winner I'm afraid, it's horses for courses.

That sounds like an interesting video! I'm surprised no other manufacturers seem to pursue a similar ASIC route even though they actually do roll their own ASICs. Rigol has just done one but achieved pretty much the opposite with a very sluggish MSO5000. It may be cheap but it's certainly not hardware accelerated to any similar degree.

Tektronix has its own A/D chips, R&S has front end chips and A/Ds. It's just that Keysight had different priorities while designing it's architecture, putting responsiveness before everything, trying to make it feel analog like. Other manufacturers went for longer memories and other functions.

[Mr. Scram]

Tektronix has its own A/D chips, R&S has front end chips and A/Ds. It's just that Keysight had different priorities while designing it's architecture, putting responsiveness before everything, trying to make it feel analog like. Other manufacturers went for longer memories and other functions.

It seems only a matter of time before Keysight pushes out a new ASIC and owns the market for another 5 years. They've definitely had success with the current generation, so it surprises me no one else is going near it. Especially considering the sluggish nature of many UIs is a common complaint.

[Howardlong]

A question I've asked before is how much memory is enough?

And the answer is, there's never enough, and it's subject to the law of diminishing returns.

However much memory you have, sooner or later you're going to need to get a bit more creative with your delaying/triggering/segmenting skills!

[2N3055]

A question I've asked before is how much memory is enough?

And the answer is, there's never enough, and it's subject to the law of diminishing returns.

However much memory you have, sooner or later you're going to need to get a bit more creative with your delaying/triggering/segmenting skills!

That is why I'm combining MSO-X3104T, Picoscope 3406D MSO with 500 MPoints, and Pico 4262 with 16 bit res.. I stopped trying to find one scope that does it all..

[Howardlong]

A question I've asked before is how much memory is enough?

And the answer is, there's never enough, and it's subject to the law of diminishing returns.

However much memory you have, sooner or later you're going to need to get a bit more creative with your delaying/triggering/segmenting skills!

That is why I'm combining MSO-X3104T, Picoscope 3406D MSO with 500 MPoints, and Pico 4262 with 16 bit res.. I stopped trying to find one scope that does it all..

...and you can never have enough scopes.

[rsjsouza]

About a month ago I had the opportunity to play with the new Tek 4 series oscilloscope and, although it has lots of features (several required extra money), the user interface was very confusing, with lots of small soft buttons to press (it is a touchscreen oscilloscope) and the speed of the overall system was very slow.

For example, with the oscilloscope either running lots of functions (decode, math, multiple channels) or none at all (single channel), I had to press three or four times the screen to access a function or close a window. When I did the selection on the screen to do zone triggering,  for several times I had to repeat the operation as the machine didn't compute my selection.

I was disappointed, as the TDS7104 (Windows 2000 based oscilloscope) was snappier than it.

[tautech]

@starlite4321

You came to EEVblog with MDO on you mind which suggests you want to cover RF use too.
Is that still a consideration because apart from the Tek you were initially looking at no other scopes cover into the RF field well.
Does the budget extend to 2 instruments ?

[starlite4321]

Man, this blog is like the frickin' Rosetta stone !  Again, thanks for all the responses!

As for the MDO question, yeah, I'm getting a good dose of reality and I can see I'm going to have to think in terms of doing this in stages.  I guess it was a bit of wishful thinking that one instrument could do it all.  At this point I think I'm going to have to think in terms of an MSO scope with "co-spectral capabilities"  (if you know what I mean - the ability to pair an FFT with a selectable/adjustable region in the time domain) which most of them seem to have, AND a separate SA.  Though I won't be able to purchase them at the same time.  I'm just going to have to live with that.  The scope trade has that constant slope of "a little more $$ gets a little more goodness" thing off to infinity so I think I'm going to decide where to cut that off by eating all the pain I can stand there first.  And just live with whatever trade that involves.

Reading the posts here, I agree that the UI responsiveness thing is extremely important and the Keysights seem to be way ahead of everybody else on that.  They also have the "Visible Trigger" thing at least in the 4000 series (not the 3000 though).  I just wish it was 10 bit instead of 8.  Also it sucks it has the large screen but crappy resolution.  WTF?  I'm feeling like I arrived at the question one iteration too soon.  I'm going to have to look at the others people are recommending more carefully also.  I guess I started from my old-days perspective where HP and Tektronix ruled the Earth.  Looks like the HP progeny still does but there are lots of other contenders now.

I just noticed the Rigol 7000 series.  Does anyone have experience with that?  Is Rigol a "safe" brand?

[David Hess]

In theory the other higher end scopes are not doing the same job an MDO is, because they don't have proper RF front ends.
But all scopes are capable of doing FFT to give you a spectrum analyser display. What performance they have depends upon the price and capabilities of the individual scope. e.g. Bandwidth, sample rate, 10/12 bit converter etc. It gets more complicated when you start talking cross-domain triggering etc, so it not an easy black and white answer.
A really high end non-MDO scope will beat the pants off a cheap(er) MDO scope, unless you need to measure really low level RF signals, then you'd need an external RF amplifier on the non-MDO scope.

I was under the impression that the big difference besides an extra vertical input optimized for RF was the DSP hardware to support real time decimation and FFT processing and that the MDO3000 lacked this limiting its mixed domain performance.

I do not remember the MSO5000 series even approaching the FFT performance of the MDO4000.

[tautech]

At this point I think I'm going to have to think in terms of an MSO scope with "co-spectral capabilities"  (if you know what I mean - the ability to pair an FFT with a selectable/adjustable region in the time domain) which most of them seem to have, AND a separate SA.  Though I won't be able to purchase them at the same time.

Think again.
How does a 200 MHz 4ch DSO with MSO capability AND a 2.1 GHz SA or 1.5 GHz SA/VNA combo for under $3k sound ?
(base units plus options)

[starlite4321]

It sounds great!  As long as the scope has the "Visible Trigger" feature and they both have good quality, large touch screen displays along with the good performance characteristics.  What do you have in mind?

[tautech]

It sounds great!  As long as the scope has the "Visible Trigger" feature and they both have good quality, large touch screen displays along with the good performance characteristics.  What do you have in mind?

Right, I forgot about zone triggering and touch where you'd need to jump up to the 350 MHz SDS5034X for those.
For the SA, SVA1015X has the same size 10" touch display but sadly the SSA models don't have touch.
That bumps the price for 2 units to just under $5k plus options if any.

[David Hess]

MDO is very nice idea in my opinion. I was kinda hoping other would adopt it and improve on it, instead, even Tek dropped it. It's a shame.

Yes, I was quite stunned when the 5 series came out and didn't have it.
Like I said, the parts cost very little, even if the spectrum analyser part isn't as good as a "real" SA.

I thought the lack of MDO in the 5 series made perfect sense.

The MDO4000 and even more so, the MDO3000, are intended as new or replacement oscilloscopes for users who currently lack or cannot afford dedicated separate RF instruments.  This would include all of the new or expected low end IoT and RF developers.

Higher end users who would buy a 5 series already have or can afford dedicated RF instruments specific to their application.

[starlite4321]

Thanks tautech - those are great suggestions!  Do you have any experience with them?  I've got this basic "you get what you pay for" fear but I think it's not that simple anymore, at least for me for at least two reasons: 1) I can't AFFORD to just buy high end stuff and, 2) it's kind of a new world now where foreign companies can really compete with the big boys at significantly lower cost so it's at least possible to find "better" stuff for less money.  Especially for companies that have been at it for a long time, building up their repertoire.

Do you have any experience with these?  Do they have reasonably fast UI's for example?  The specs look pretty amazing given the price though I see the scope is still 8-bit.  I'm not hard over about that, it would just be nice if the design could support a lower noise floor and had the resolution to take advantage of it.  It looks like most things are 8 bit at this point so it's not like it's holding the world back or anything.

Along roughly similar lines, I just noticed the Rigol's have big free upgrade offers going.  In the case of the 7000 series scope, the upgrade is worth more than the damn scope!  Pretty amazing!

I will definitely look into these guys.  Again, thanks!

[maginnovision]

Thanks tautech - those are great suggestions!  Do you have any experience with them?  I've got this basic "you get what you pay for" fear but I think it's not that simple anymore, at least for me for at least two reasons: 1) I can't AFFORD to just buy high end stuff and, 2) it's kind of a new world now where foreign companies can really compete with the big boys at significantly lower cost so it's at least possible to find "better" stuff for less money.  Especially for companies that have been at it for a long time, building up their repertoire.

Do you have any experience with these?  Do they have reasonably fast UI's for example?  The specs look pretty amazing given the price though I see the scope is still 8-bit.  I'm not hard over about that, it would just be nice if the design could support a lower noise floor and had the resolution to take advantage of it.  It looks like most things are 8 bit at this point so it's not like it's holding the world back or anything.

Along roughly similar lines, I just noticed the Rigol's have big free upgrade offers going.  In the case of the 7000 series scope, the upgrade is worth more than the damn scope!  Pretty amazing!

I will definitely look into these guys.  Again, thanks!

Hahaha, the Rigol 7000 may well be what tautech was thinking about. Good luck with your search.

[tautech]

Thanks tautech - those are great suggestions!  Do you have any experience with them? 

Yep, I own and use both.
Disclosure in case you hadn't linked me to selling these but only in NZ as that is my authorised territory.

SDS5kX series is relatively new and is a work in progress in that the the publically available product release firmware has undergone several iterations since even Dave reviewed this scope but it's still in the beta stages and several improvements been added for when it finally sees the light of day. I have the latest beta FW on my 500 MHz model and have suggested further improvements to be made.

SVA1015X is a powerful tool and this too has recently undergone a significant upgrade since anyone has publically reviewed it in preparation for release of a bigger brother that will extend SA/VNA capabilities to 3.2 GHz.

[2N3055]

MDO is very nice idea in my opinion. I was kinda hoping other would adopt it and improve on it, instead, even Tek dropped it. It's a shame.

Yes, I was quite stunned when the 5 series came out and didn't have it.
Like I said, the parts cost very little, even if the spectrum analyser part isn't as good as a "real" SA.

I thought the lack of MDO in the 5 series made perfect sense.

The MDO4000 and even more so, the MDO3000, are intended as new or replacement oscilloscopes for users who currently lack or cannot afford dedicated separate RF instruments.  This would include all of the new or expected low end IoT and RF developers.

Higher end users who would buy a 5 series already have or can afford dedicated RF instruments specific to their application.

I believe you're missing the point. RF part doesn't need to be excellent SA. It has to be adequate and realtime with very high POI. It is there to correlate events, not to measure advanced stuff you would with real SA.

[starlite4321]

Hi tautech, again thanks for the response.  Yeah, ok, I see.  I didn't notice you're a dealer for Siglent in NZ - bone head me. Guess its not fair to be asking you about Rigols!  Well, that only means you know them very well which is very valuable.  People have commented that the touch screen UI's on most stuff besides the Keysight's are pretty sluggish.  How are the Siglents in that regard?  And does Siglent have corresponding upgrade options to Rigol's?

[tautech]

People have commented that the touch screen UI's on most stuff besides the Keysight's are pretty sluggish.  How are the Siglents in that regard?  And does Siglent have corresponding upgrade options to Rigol's?

Pretty snappy but look at Daves video to get a proper idea of the release firmware responsiveness.


Currently there isn't any SDS5kX option bundle prices but as a package deal most dealers will sharpen their pencil some.
The SDS5kX US website:
https://www.siglentamerica.com/digital-oscilloscopes/sds5000x/
Check out Authorized Partners to find your local seller or chase the Saelig thread I linked earlier for 6% off as an EEVblog member.

[ogden]

The MDO4000 and even more so, the MDO3000, are intended as new or replacement oscilloscopes for users who currently lack or cannot afford dedicated separate RF instruments.

Those who think that they can't afford something, shall not consider Tek products in the first place

MDO3000 indeed could be for users who are fine with built-in basic & quite limited SA, yet I disagree about MDO4000. Better do not buy MDO4000 unless you actually need mixed domain function. DSP guy who develops RF transceiver ASIC's or SDR's could find such instrument handy. Those RF engineers who design IoT/whatever using 3rd party radio IC's most likely will be fine with ordinary, standalone spectrum analyzer.

Good demonstration what mixed domain scope actually is:  https://youtu.be/WBDS9ebDLhg?t=1

[starlite4321]

Not sure if the EEVblog admin is still looking at this thread but if so, I have a question.  When I was asking about "zone triggering" several posts back you said, "It's called "zone triggering" and the RTM3000 has it too. And yes, it's a real handy feature on modern touch screen scopes.".  I've just spent some time looking at the R&S website and as far as I can see, R&S doesn't offer "zone triggering" until you get to their RTO2000 model which starts at $14,000!!  Are you saying they've added it to the RTM3000 via a recent firmware update or something and just haven't updated their website (or it has an error)?  If so, that would be great!

[EEVblog]

That sounds like an interesting video! I'm surprised no other manufacturers seem to pursue a similar ASIC route even though they actually do roll their own ASICs. Rigol has just done one but achieved pretty much the opposite with a very sluggish MSO5000. It may be cheap but it's certainly not hardware accelerated to any similar degree.

And it doesn't have for some strange reason, HiRes capability. Crazy.

[EEVblog]

Not sure if the EEVblog admin is still looking at this thread but if so, I have a question.  When I was asking about "zone triggering" several posts back you said, "It's called "zone triggering" and the RTM3000 has it too. And yes, it's a real handy feature on modern touch screen scopes.".  I've just spent some time looking at the R&S website and as far as I can see, R&S doesn't offer "zone triggering" until you get to their RTO2000 model which starts at $14,000!!  Are you saying they've added it to the RTM3000 via a recent firmware update or something and just haven't updated their website (or it has an error)?  If so, that would be great!

Yeah, sorry, was searching a comparison datasheet, not an individual datasheet. RTO only it seems

[starlite4321]

Dang... Well, it seems like a lot of their competition does have it.  Maybe they'll add it in a future update.  It might turn out to be one of those things you think you'll use all the time but actually don't in the end.  All I know is out of about a zillion last second hardware nightmares in the dim past, one that still sticks in my mind would have been SO much easier to pin down if we'd had something like that back in the stone age.  R&S also has a whopper upgrade offer going and reviews of their stuff look pretty good.  Thanks again for the super fast response!

[Howardlong]

FWIW, Keysight are offering MSOX3104T fully loaded with probes, software options and a 1 year warranty for US$ 6848 in their ebay store at the moment. The only thing I'd recommend adding to the spec would be a LAN interface card.

https://www.ebay.com/itm/193024964977

The 3000T series offer both zone triggering and FFT gating (as well the usual Keysight Infiniivision slick UI, which to me is by far the most important feature!).

[EEVblog]

It seems only a matter of time before Keysight pushes out a new ASIC and owns the market for another 5 years. They've definitely had success with the current generation, so it surprises me no one else is going near it. Especially considering the sluggish nature of many UIs is a common complaint.

IIRC they averaged 8 years between Megazoom ASIC's and it's now been 10 years.
The two obvious things to improve are the memory size and the display resolution. I really hope they make it 1920x1080 capable with external HDMI support, that would be sweet. Internal screen doesn't have to do that, but better external resolution would be something no one else is doing.
They really don't have to improve much else, because 10 years later it still beats practically everyone else in hardware decoding and responsiveness.

[EEVblog]

Thanks tautech - those are great suggestions!  Do you have any experience with them?

Be aware that Tautech is a Siglent distributor, so he has a vested interest in talking up Siglent and does so at every opportunity on the forum, he's (in)famous for it.

[EEVblog]

Do you have any experience with these?  Do they have reasonably fast UI's for example?

Siglent UI responsiveness is very good, one of the better ones out there.

[EEVblog]

Tektronix has its own A/D chips, R&S has front end chips and A/Ds. It's just that Keysight had different priorities while designing it's architecture, putting responsiveness before everything, trying to make it feel analog like. Other manufacturers went for longer memories and other functions.

Actually, the Megazoom IV ASIC was released over 10 years ago now, and would have been developed for many years before that. Back then 4M of memory, especially fast integrated memory with hardware segmenting etc was a lot of memory. They owned the market when the 2000/3000 X series were released, no one else could touch it for a good 4-5 years. Now 10 years on the 4M looks small for sure, but it's still the fastest thing on the market. And that chip is built into their base model 1000X units, so at any time they can release a firmware upgrade and make a killer low end product.

[Mr. Scram]

FWIW, Keysight are offering MSOX3104T fully loaded with probes, software options and a 1 year warranty for US$ 6848 in their ebay store at the moment. The only thing I'd recommend adding to the spec would be a LAN interface card.

https://www.ebay.com/itm/193024964977

The 3000T series offer both zone triggering and FFT gating (as well the usual Keysight Infiniivision slick UI, which to me is by far the most important feature!).

Note that the offering is for used equipment and not what Keysight calls Premium Used. It's still a deal to consider, but it'd be good to confirm the equipment condition and warranty are what you're looking for.

[Mr. Scram]

Thanks tautech - those are great suggestions!  Do you have any experience with them?  I've got this basic "you get what you pay for" fear but I think it's not that simple anymore, at least for me for at least two reasons: 1) I can't AFFORD to just buy high end stuff and, 2) it's kind of a new world now where foreign companies can really compete with the big boys at significantly lower cost so it's at least possible to find "better" stuff for less money.  Especially for companies that have been at it for a long time, building up their repertoire.

Do you have any experience with these?  Do they have reasonably fast UI's for example?  The specs look pretty amazing given the price though I see the scope is still 8-bit.  I'm not hard over about that, it would just be nice if the design could support a lower noise floor and had the resolution to take advantage of it.  It looks like most things are 8 bit at this point so it's not like it's holding the world back or anything.

Along roughly similar lines, I just noticed the Rigol's have big free upgrade offers going.  In the case of the 7000 series scope, the upgrade is worth more than the damn scope!  Pretty amazing!

I will definitely look into these guys.  Again, thanks!

Chinese manufacturers have been steadily improving their act. Their support level still isn't on par with the higher end parties, though. Firmware support has been hit and miss and repair and parts availability shouldn't be relied on. If you're looking at the Chinese options you may want to look at the Rigol MSO5000 that was released recently. It's a mixed bag, they definitely have some firmware work ahead of them and the UI isn't as responsive as you'd like but with the non-manufacturer unlock it's a 350 MHz oscilloscope for under a $1000.

[Howardlong]

FWIW, Keysight are offering MSOX3104T fully loaded with probes, software options and a 1 year warranty for US$ 6848 in their ebay store at the moment. The only thing I'd recommend adding to the spec would be a LAN interface card.

https://www.ebay.com/itm/193024964977

The 3000T series offer both zone triggering and FFT gating (as well the usual Keysight Infiniivision slick UI, which to me is by far the most important feature!).

Note that the offering is for used equipment and not what Keysight calls Premium Used. It's still a deal to consider, but it'd be good to confirm the equipment condition and warranty are what you're looking for.

When I receive mine I'll report back ;-)

In the meantime I've been delighted with my MSO7104B for the past four years or so I've had it from the same source, which came without probes or warranty beyond the standard 30 days.

[Mr. Scram]

IIRC they averaged 8 years between Megazoom ASIC's and it's now been 10 years.
The two obvious things to improve are the memory size and the display resolution. I really hope they make it 1920x1080 capable with external HDMI support, that would be sweet. Internal screen doesn't have to do that, but better external resolution would be something no one else is doing.
They really don't have to improve much else, because 10 years later it still beats practisplay ally everyone else in hardware decoding and responsiveness.

I agree with the necessary display resolution and memory upgrade. The resolution really isn't bad but it's starting to lag behind the competition. It's mystifying how everyone cites the responsiveness of the Keysight and nobody else is even trying to copy it. I know it's not a big number on the specification sheet but it's obviously why many people like the oscilloscopes.


I know many other brands don't come anywhere near the listed waveform updates or only under very specific conditions. How's that with the Keysights? I think those are doing quite well in that regard?

[Fungus]

That sounds like an interesting video! I'm surprised no other manufacturers seem to pursue a similar ASIC route

It's very expensive to do.

Rigol has just done one but achieved pretty much the opposite with a very sluggish MSO5000. It may be cheap but it's certainly not hardware accelerated to any similar degree.

I think the Rigol ASIC is only for the front end, not the actual processing.

The "problem" the Rigol 5000 has is 400Mb of RAM (vs. 1Mb in the Keysight...)

The big advantage of the Rigol is that you can buy the $900 model and unlock all the features to get the $5000 model.

[rsjsouza]

IIRC they averaged 8 years between Megazoom ASIC's and it's now been 10 years.
The two obvious things to improve are the memory size and the display resolution. I really hope they make it 1920x1080 capable with external HDMI support, that would be sweet. Internal screen doesn't have to do that, but better external resolution would be something no one else is doing.
They really don't have to improve much else, because 10 years later it still beats practisplay ally everyone else in hardware decoding and responsiveness.

I agree with the necessary display resolution and memory upgrade. The resolution really isn't bad but it's starting to lag behind the competition. It's mystifying how everyone cites the responsiveness of the Keysight and nobody else is even trying to copy it. I know it's not a big number on the specification sheet but it's obviously why many people like the oscilloscopes.


I know many other brands don't come anywhere near the listed waveform updates or only under very specific conditions. How's that with the Keysights? I think those are doing quite well in that regard?

I think you answered yourself. The specification sheet will never be able to objectively state the amount of "responsiveness" of the UI - a key component when you are trying to go after the brochure/spec numbers game with your competitors.

It is easier and much more certain to throw more money (i.e., memory, GSPS, resolution, etc.) into the problem instead of making an expensive investment in a decent user interface that yields a more uncertain return.

Rigol has just done one but achieved pretty much the opposite with a very sluggish MSO5000. It may be cheap but it's certainly not hardware accelerated to any similar degree.

I think the Rigol ASIC is only for the front end, not the actual processing.

The Phoenix chipset seems to encompass a lot of other functions, including processing. 

[2N3055]

The Phoenix chipset seems to encompass a lot of other functions, including processing. 

That is correct. But problem is that many here are discussing "scope responsiveness" without explaining what it means.
Keysight 3000T has many things in hardware, but they "windows" part, the UI, is the one that is so fast.
Rigol MSO5000 has very fast acquisition engine (not as fast as Keysight but very fast), and even FFT and other things are not slow. What is slow is windowing interface, the UI.  You move something on the screen, it is slow. Same thing with R&S 3000, try scrolling horizontally with  a finger...

Where all these manufacturers are not doing very good job is in the UI. Most of them seem to use some ready made windowing library, that seems to be not very good choice for real time graphical instrument..

[Mr. Scram]

That is correct. But problem is that many here are discussing "scope responsiveness" without explaining what it means.
Keysight 3000T has many things in hardware, but they "windows" part, the UI, is the one that is so fast.
Rigol MSO5000 has very fast acquisition engine (not as fast as Keysight but very fast), and even FFT and other things are not slow. What is slow is windowing interface, the UI.  You move something on the screen, it is slow. Same thing with R&S 3000, try scrolling horizontally with  a finger...

Where all these manufacturers are not doing very good job is in the UI. Most of them seem to use some ready made windowing library, that seems to be not very good choice for real time graphical instrument..

It's probably pretty obvious what "scope responsiveness" means if you've ever used a Keysight. It's not just the UI. Turning on features means adding internal computations being done. Most of that is done in hardware on the Keysights, so there's no slowdown. Not just visually, but the actual work being done doesn't slow down either. The UI is also done in the MegaZoom IV ASIC, only some very specific things are done separately by the CPU. See page 4 of this document.

http://literature.cdn.keysight.com/litweb/pdf/5990-7906EN.pdf

[Mr. Scram]

I think you answered yourself. The specification sheet will never be able to objectively state the amount of "responsiveness" of the UI - a key component when you are trying to go after the brochure/spec numbers game with your competitors.

It is easier and much more certain to throw more money (i.e., memory, GSPS, resolution, etc.) into the problem instead of making an expensive investment in a decent user interface that yields a more uncertain return.

The Phoenix chipset seems to encompass a lot of other functions, including processing.

Sure it's not on the specifications sheet, but the one party doing it is definitely doing well.

[2N3055]

That is correct. But problem is that many here are discussing "scope responsiveness" without explaining what it means.
Keysight 3000T has many things in hardware, but they "windows" part, the UI, is the one that is so fast.
Rigol MSO5000 has very fast acquisition engine (not as fast as Keysight but very fast), and even FFT and other things are not slow. What is slow is windowing interface, the UI.  You move something on the screen, it is slow. Same thing with R&S 3000, try scrolling horizontally with  a finger...

Where all these manufacturers are not doing very good job is in the UI. Most of them seem to use some ready made windowing library, that seems to be not very good choice for real time graphical instrument..

It's probably pretty obvious what "scope responsiveness" means if you've ever used a Keysight. It's not just the UI. Turning on features means adding internal computations being done. Most of that is done in hardware on the Keysights, so there's no slowdown. Not just visually, but the actual work being done doesn't slow down either. The UI is also done in the MegaZoom IV ASIC, only some very specific things are done separately by the CPU. See page 4 of this document.

http://literature.cdn.keysight.com/litweb/pdf/5990-7906EN.pdf

That is right. But pretty much all math and fft is done by accelerators in MSO5000. What is  slow is pretty much stupid U/I things, same as with R&S 3000. Sad part is that cheap tablets and phones are doing it much better and faster...
Siglent SDS5000X does it much, much better then the rest.

[rsjsouza]

That is correct. But problem is that many here are discussing "scope responsiveness" without explaining what it means.
Keysight 3000T has many things in hardware, but they "windows" part, the UI, is the one that is so fast.
Rigol MSO5000 has very fast acquisition engine (not as fast as Keysight but very fast), and even FFT and other things are not slow. What is slow is windowing interface, the UI.  You move something on the screen, it is slow. Same thing with R&S 3000, try scrolling horizontally with  a finger...

Where all these manufacturers are not doing very good job is in the UI. Most of them seem to use some ready made windowing library, that seems to be not very good choice for real time graphical instrument..

I see several non-mainstream products using ready made windowing libraries (Qt, Android, etc.) that are  capable of delivering a decent UI on a regular applications processor (Cortex A). Given these oscilloscope chipsets already partition the system in a way to offload the number crunching away from the UI CPU, it should be a matter of directing resources to actually work on this aspect of the equipment. That is not cheap.

That is right. But pretty much all math and fft is done by accelerators in MSO5000. What is  slow is pretty much stupid U/I things, same as with R&S 3000.

Add the newest Tek 3 and 4 series there.

Sad part is that cheap tablets and phones are doing it much better and faster...

UI requires a reasonable amount of resources in the shape of developers and, most importantly, testers - but these are working for the lush green$ of the consumer industry... 

[egonotto]

Hello

EEVblog wrote: "It's called "zone triggering" and the RTM3000 has it too".

Are you sure? I don't find it in the datasheet and in the user manual. R&S says "zone trigger" is advanced and is only in RTO2000 and RTP (as an option)

Best regards
egonotto
 

[maginnovision]

No zone, just mask. Should usually be useful in same ways since it'll save fails in history. Or I don't know what people use zone trigger for, I've never used it even in scopes that had it.

[EEVblog]

That is correct. But problem is that many here are discussing "scope responsiveness" without explaining what it means.
Keysight 3000T has many things in hardware, but they "windows" part, the UI, is the one that is so fast.
Rigol MSO5000 has very fast acquisition engine (not as fast as Keysight but very fast), and even FFT and other things are not slow. What is slow is windowing interface, the UI.  You move something on the screen, it is slow. Same thing with R&S 3000, try scrolling horizontally with  a finger...

Where all these manufacturers are not doing very good job is in the UI. Most of them seem to use some ready made windowing library, that seems to be not very good choice for real time graphical instrument..

It's probably pretty obvious what "scope responsiveness" means if you've ever used a Keysight. It's not just the UI. Turning on features means adding internal computations being done. Most of that is done in hardware on the Keysights, so there's no slowdown. Not just visually, but the actual work being done doesn't slow down either. The UI is also done in the MegaZoom IV ASIC, only some very specific things are done separately by the CPU. See page 4 of this document.

http://literature.cdn.keysight.com/litweb/pdf/5990-7906EN.pdf

Yes, and this why the 4000X series with it's much larger screen had to use the same 800x600 resolution as the small models, because all the screen stuff is mapped in the ASIC with a fixed resolution.

[David Hess]

Sad part is that cheap tablets and phones are doing it much better and faster...

I test them occasionally and have never found them to have good or even acceptable responsiveness.

The objective test is *maximum* latency between a command input and a result.  Given a 60 Hz display, anything up to 33 milliseconds is acceptable and they cannot even meet that.  Having the display pause while garbage collection or something is going on is particularly annoying.

[Howardlong]

That is correct. But problem is that many here are discussing "scope responsiveness" without explaining what it means.
Keysight 3000T has many things in hardware, but they "windows" part, the UI, is the one that is so fast.
Rigol MSO5000 has very fast acquisition engine (not as fast as Keysight but very fast), and even FFT and other things are not slow. What is slow is windowing interface, the UI.  You move something on the screen, it is slow. Same thing with R&S 3000, try scrolling horizontally with  a finger...

Where all these manufacturers are not doing very good job is in the UI. Most of them seem to use some ready made windowing library, that seems to be not very good choice for real time graphical instrument..

It's probably pretty obvious what "scope responsiveness" means if you've ever used a Keysight. It's not just the UI. Turning on features means adding internal computations being done. Most of that is done in hardware on the Keysights, so there's no slowdown. Not just visually, but the actual work being done doesn't slow down either. The UI is also done in the MegaZoom IV ASIC, only some very specific things are done separately by the CPU. See page 4 of this document.

http://literature.cdn.keysight.com/litweb/pdf/5990-7906EN.pdf

Yes, and this why the 4000X series with it's much larger screen had to use the same 800x600 resolution as the small models, because all the screen stuff is mapped in the ASIC with a fixed resolution.

Interestingly the previous Megazoom III used in the older generation 5000, 6000 and 7000 scopes supports XGA and 8Mpts, with a ~1000x640 pixel waveform area, almost the entire width of the display is used unlike the Megazoom IV which looks like a waveform area of about 640x384 pixels.

Megazoom III also supported 8Mpts compared to 4Mpts of Megazoom IV.

I’m not sure if this is ASIC dependent, but the digital channel sample rate of the older generation is 2Gsa/s compared to 1Gsa/s in the current generation of Infiniivision scopes.

[EEVblog]

Interestingly the previous Megazoom III used in the older generation 5000, 6000 and 7000 scopes supports XGA and 8Mpts, with a ~1000x640 pixel waveform area, almost the entire width of the display is used unlike the Megazoom IV which looks like a waveform area of about 640x384 pixels.
Megazoom III also supported 8Mpts compared to 4Mpts of Megazoom IV.

IIRC the Megazoom III used external memory. The IV 4Msamples is on the die, that's why it's so quick.

[EEVblog]

No zone, just mask. Should usually be useful in same ways since it'll save fails in history. Or I don't know what people use zone trigger for, I've never used it even in scopes that had it.

Zone trigger lets you just draw a box around the area on the waveform you want to trigger on and it just does it. very handy.

[Howardlong]

Interestingly the previous Megazoom III used in the older generation 5000, 6000 and 7000 scopes supports XGA and 8Mpts, with a ~1000x640 pixel waveform area, almost the entire width of the display is used unlike the Megazoom IV which looks like a waveform area of about 640x384 pixels.
Megazoom III also supported 8Mpts compared to 4Mpts of Megazoom IV.

IIRC the Megazoom III used external memory. The IV 4Msamples is on the die, that's why it's so quick.

Sounds reasonable.

I assume by "quick" you're referring to the waveform update rate, and not the scope UX.

If that is the case, then just like memory depth, I'd suggest that we're back to diminishing returns: once you have, say, 100kWfm/s (Megazoom III speed), practically speaking how often are you going to benefit from 1MWfm/s?

[Mr. Scram]

Sounds reasonable.

I assume by "quick" you're referring to the waveform update rate, and not the scope UX.

If that is the case, then just like memory depth, I'd suggest that we're back to diminishing returns: once you have, say, 100kWfm/s (Megazoom III speed), practically speaking how often are you going to benefit from 1MWfm/s?

Every day to never, depending on your workload. A testing station in a production environment would benefit from doing a large amounts of masking tests within a few seconds.

[nctnico]

Interestingly the previous Megazoom III used in the older generation 5000, 6000 and 7000 scopes supports XGA and 8Mpts, with a ~1000x640 pixel waveform area, almost the entire width of the display is used unlike the Megazoom IV which looks like a waveform area of about 640x384 pixels.
Megazoom III also supported 8Mpts compared to 4Mpts of Megazoom IV.

IIRC the Megazoom III used external memory. The IV 4Msamples is on the die, that's why it's so quick.

That is not it. This scope uses some kind of parallel acquisition system which helps to increase waveform update speed (note to others: this high rate only works at a few time/div settings). Math is done on sub-sampled data so that increases performance too (probably combined with a DSP inside the ASIC). A modern FPGA can do better (both in memory bandwidth and calculations). It is just that you get in an area with diminishing returns versus investment in FPGA development.

[EEVblog]

Interestingly the previous Megazoom III used in the older generation 5000, 6000 and 7000 scopes supports XGA and 8Mpts, with a ~1000x640 pixel waveform area, almost the entire width of the display is used unlike the Megazoom IV which looks like a waveform area of about 640x384 pixels.
Megazoom III also supported 8Mpts compared to 4Mpts of Megazoom IV.

IIRC the Megazoom III used external memory. The IV 4Msamples is on the die, that's why it's so quick.

Sounds reasonable.

I assume by "quick" you're referring to the waveform update rate, and not the scope UX.

If that is the case, then just like memory depth, I'd suggest that we're back to diminishing returns: once you have, say, 100kWfm/s (Megazoom III speed), practically speaking how often are you going to benefit from 1MWfm/s?

It's not just that. It can do everything faster like the multiple get trigger point mode, masking, serial decode info and a host of other stuff, all without slowing down the UI.
I'm not sure if the Megazoom III did all the memory->screen mapping in the chip like the IV does?

[nctnico]

The UI responsiveness is just a matter of how the processes in the CPU are prioritised. Every DSO uses an ASIC or FPGA to map the waveforms onto the screen so that is also not new. Using the CPU to map waveforms onto the screen is going to be too slow. But there are many drawbacks to the Megazoom ASIC. Try to move / scale reference traces for example. On the Agilent MSO7104A I had this wasn't possible (probably the same for using cursors on the reference traces). Also the UI on the MSO7104A was horrible to use compared to the other oscilloscopes I have now. Fast UI but still slow to operate.

[SWR]

Tek is the only one that makes an "MDO" scope, it's pretty much a niche product in the mid range scope category.

Weeeell... It's not to be pedantic, but other MDO options are available in the market.

GW Instek makes a MDO-2000 series of scopes that addresses some of the issues discussed in this thread:
- High resolution 1Mpoint FFT with quick update rate.
- 40Msample memory.
- SA type UI where you don't have to adjust resolution etc. in the time domain.
- Nice broad selection of math functions on Ch1-4, Ref1-4: (the Teks limited math ability was mentioned earlier in this thread)
      Measurement Pk-Pk,Max,Min,Amp,High,Low,Mean,CycleMean,RMS,CycleRMS,Area,CycleArea,
                          ROvShoot,FOvShoot,Freq,Period,Rise,Fall,PosWidth,NegWidth,Dutycycle,
                          FRR,FRF,FFR,FFF,LRR,LRF,LFR,LFF,Phase,RPRFShoot,FPREShoot,
                          +Pulses,-Pulses,+Edges,-Edges
      Operators      +,-,*,/,<,>,<=,>=,==,!=,||,&&,
      Functions       Intg,Diff,Log,Ln,Exp,Sqrt,Abs,Rad,Deg,Sin,Cos,Tan,Asin,Acos,Atan

The UI is pretty snappy to work with on my MDO-2004EX. I assume it's equally fast on the "high end" scopes, but I have no experience (I'm always on a budget). We've got Tek and Keysight at work and they are not faster to work with in the daily work. IMO they found a nice low cost way to make the scope fast by integrating both the processor and FPGA on a Xilinx single chip solution. It's both cheaper and faster to communicate on the same chip than going via the PCB.

It might be worth considering if your funds are limited and you have to maximize your value for money?

Best regards
Soren

[2N3055]

Tek is the only one that makes an "MDO" scope, it's pretty much a niche product in the mid range scope category.

Weeeell... It's not to be pedantic, but other MDO options are available in the market.

GW Instek makes a MDO-2000 series of scopes that addresses some of the issues discussed in this thread:
- High resolution 1Mpoint FFT with quick update rate.
- 40Msample memory.
- SA type UI where you don't have to adjust resolution etc. in the time domain.
- Nice broad selection of math functions on Ch1-4, Ref1-4: (the Teks limited math ability was mentioned earlier in this thread)
      Measurement Pk-Pk,Max,Min,Amp,High,Low,Mean,CycleMean,RMS,CycleRMS,Area,CycleArea,
                          ROvShoot,FOvShoot,Freq,Period,Rise,Fall,PosWidth,NegWidth,Dutycycle,
                          FRR,FRF,FFR,FFF,LRR,LRF,LFR,LFF,Phase,RPRFShoot,FPREShoot,
                          +Pulses,-Pulses,+Edges,-Edges
      Operators      +,-,*,/,<,>,<=,>=,==,!=,||,&&,
      Functions       Intg,Diff,Log,Ln,Exp,Sqrt,Abs,Rad,Deg,Sin,Cos,Tan,Asin,Acos,Atan

The UI is pretty snappy to work with on my MDO-2004EX. I assume it's equally fast on the "high end" scopes, but I have no experience (I'm always on a budget). We've got Tek and Keysight at work and they are not faster to work with in the daily work. IMO they found a nice low cost way to make the scope fast by integrating both the processor and FPGA on a Xilinx single chip solution. It's both cheaper and faster to communicate on the same chip than going via the PCB.

It might be worth considering if your funds are limited and you have to maximize your value for money?

Best regards
Soren

GW Instek MDO was mentioned already.  I agree with you as it being quality product and very good, but it is not really same as Tek MDO. There is no time domain correlation between time domain channels and FFT.
That is the distinctive feature, of Tek MDO, and Keysight and LeCroy gated FFT are similar to it. Still, Tek  can trigger on RF event, that others can't ...

[EEVblog]

Tek is the only one that makes an "MDO" scope, it's pretty much a niche product in the mid range scope category.

Weeeell... It's not to be pedantic, but other MDO options are available in the market.

GW Instek makes a MDO-2000 series of scopes that addresses some of the issues discussed in this thread:
- High resolution 1Mpoint FFT with quick update rate.
- 40Msample memory.
- SA type UI where you don't have to adjust resolution etc. in the time domain.

It uses a standard scope front end, so it's just a software solution, not the same as the Tek MDO that has a real RF front end.

is it any different to Keysight gated FFT etc really?

[2N3055]

Tek is the only one that makes an "MDO" scope, it's pretty much a niche product in the mid range scope category.

Weeeell... It's not to be pedantic, but other MDO options are available in the market.

GW Instek makes a MDO-2000 series of scopes that addresses some of the issues discussed in this thread:
- High resolution 1Mpoint FFT with quick update rate.
- 40Msample memory.
- SA type UI where you don't have to adjust resolution etc. in the time domain.

It uses a standard scope front end, so it's just a software solution, not the same as the Tek MDO that has a real RF front end.

is it any different to Keysight gated FFT etc really?

SA mode is made same as on Tek MDO3000, it's an exclusive screen mode and no correlation with other data..

[ogden]

It uses a standard scope front end, so it's just a software solution, not the same as the Tek MDO that has a real RF front end.

Gains from RF frontend of Tek MDO3000 are - better sensitivity, SNR and freq response. That's it. Main value is signal processing. I would not include MDO4000 in comparison because it is another class of instrument.

is it any different to Keysight gated FFT etc really?

They are different things. AFAIK gated FFT of Keysight is about frequency analysis of recorded samples in the gated time window.

I see that Keysight (like 3000T X-Series) have same FFT features - Start Frequency, Stop Frequency, Center Frequency and Span controls. Seeing very good FFT update rate of FFT GW Instek MDO-2000 I can tell that they use digital downconversion (DDC) before FFT. Dunno about Keysight. It is much more efficient to downconvert frequency range of interest into baseband, calculate FFT-1024 and show every of 1024 freq bins on the screen rather than calculate 1M FFT points, waste 99.9% compute resources to show just 1024 points. Performance difference is gigantic between two. With DDC+FFT1024 one can achieve realtime spectrum analysis, using 1M FFT - never.

SA mode is made same as on Tek MDO3000, it's an exclusive screen mode and no correlation with other data..

IMHO it's cheating to call it Mixed Domain Oscilloscope without correlation between time and frequency domain displays.

[2N3055]

IMHO it's cheating to call it Mixed Domain Oscilloscope without correlation between time and frequency domain displays.

I agree, both Tek MDO3000 and GW Instek are not really MDO in my opinion. Only Tek MDO4000.

[Howardlong]

I had a quick look at a couple of videos on the MDO2000E, one concentrating on the SA, and the close in phase noise looked pretty bad, I assume it's from their reference clock and/or PLL. Perhaps it was just the example they gave.

[Howardlong]

IMHO it's cheating to call it Mixed Domain Oscilloscope without correlation between time and frequency domain displays.

I tend to agree, and I fell into that trap when I bought an MDO3000: I assumed that there was some operational integration between the scope and the SA, like the MDO4000 has, but all it is is an SA and scope in the same box, and they cannot run concurrently, and as such it certainly doesn't offer any time/frequency domain correlation. That missing feature is noticeable only by its absence in the marketing blurb.

[Mr. Scram]

The UI responsiveness is just a matter of how the processes in the CPU are prioritised. Every DSO uses an ASIC or FPGA to map the waveforms onto the screen so that is also not new. Using the CPU to map waveforms onto the screen is going to be too slow. But there are many drawbacks to the Megazoom ASIC. Try to move / scale reference traces for example. On the Agilent MSO7104A I had this wasn't possible (probably the same for using cursors on the reference traces). Also the UI on the MSO7104A was horrible to use compared to the other oscilloscopes I have now. Fast UI but still slow to operate.

The current generation is the Megazoom IV ASIC which allows scaling, cursors and measurements on reference waveforms in the same expedient manner as any waveform.

[2N3055]

The UI responsiveness is just a matter of how the processes in the CPU are prioritised. Every DSO uses an ASIC or FPGA to map the waveforms onto the screen so that is also not new. Using the CPU to map waveforms onto the screen is going to be too slow. But there are many drawbacks to the Megazoom ASIC. Try to move / scale reference traces for example. On the Agilent MSO7104A I had this wasn't possible (probably the same for using cursors on the reference traces). Also the UI on the MSO7104A was horrible to use compared to the other oscilloscopes I have now. Fast UI but still slow to operate.

The current generation is the Megazoom IV ASIC which allows scaling, cursors and measurements on reference waveforms in the same expedient manner as any waveform.

Correct. In my opinion, 3000T is close to being perfect except FFT being only 64kpoints (not a big deal for me anyway), and not having larger acq memory. If they had 10Mpoints per ch (like GW Instek) it would be pretty much fantastic, current memory is OKish, but sometimes it needs more... Also, one thing that is not intuitive is that if you capture something, you see that it is something resembling some protocol, you cannot just enable protocol decode after the fact and see what it says. You need to recapture. Also if you are not sure about parameters, you will have to keep changing parameters and recapturing until you get it right, and then start your work. Not a problem when working on something that spits out 100 packets per second, but when working at something that occasionally sends a packet it is not that nice..
Those are the moments when I switch to Pico that has 500MPoints, and decodes in software, so I can capture and analyse offline..

[Howardlong]

That's pretty much my modus operandi also. Use the go-to scope for 90% to 95% of things, then for the remaining cases leverage those key differentiating features.

The downside of this approach is that as a result you tend not to be as experienced in using those other instruments, and, in the case of complex instruments, you can easily forget how to do things, or not be fully aware of their capabilities and quirks.

[2N3055]

That's pretty much my modus operandi also. Use the go-to scope for 90% to 95% of things, then for the remaining cases leverage those key differentiating features.

The downside of this approach is that as a result you tend not to be as experienced in using those other instruments, and, in the case of complex instruments, you can easily forget how to do things, or not be fully aware of their capabilities and quirks.

When I got 3000T, it was quite a work to absorb manuals and materials. It was very useful that scope has demo/teaching mode and corresponding two educators manuals that are excellent to quickly get an idea of features. Also they have applications notes for pretty much every protocol and feature that also show how to do it and even some little tricks that are not obvious for first time users

But you will only know from top of your head things that you do often.
One thing that I find useful, though, is that most of the time for questions like: "does it have this source for this trigger? can I apply this measurement on this etc.." that quickest and most concise source is not the user manual, but the SCPI commands programmers manual.