Tektronix Mixed Domain MDO4000 Review - Page 1
Forum section: electronics / testgear

author: EEVblog
author_rank: Unknown
timestamp: August 30, 2011, 11:31:13 am
content: Is now up:and the teardown:Still uploading podcast version to the blog site.Comments and discussion here.Dave.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 30, 2011, 01:31:46 pm
content: Agree that the plug-in modules are dumb - ISTR reading they are just eeproms (and have been hacked).As well as being less flexible than Agilent's system, they are also less secure as if one gets hacked it works on every scope.And it does seem a bit of a pisstake to have something like serial decode an option on a scope this expensive.Might be interesting to compare speeds between Tek and Agilent on serial decode -ISTR reading somewhere (Possibly Agilent literature) that the Tek is software compared to the Agilent doing it in FPGA, although that may have been on lower-end Tek models.BTW that mains coupling - were those wires connected at the PSU end, or insulated and just just capacitively coupled?

author: EEVblog
author_rank: Unknown
timestamp: August 30, 2011, 01:35:53 pm
content: Quote from: mikeselectricstuff on August 30, 2011, 01:31:46 pmIIRC Agilent claim hardware serial decode on their new X series and the higher end series too. No performance penalty for using it.Tek I believe is all software?QuoteInsulated and just cap coupled. You should be able to see that in the video if you look close.Dave.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 30, 2011, 01:44:44 pm
content: This is where I read about the modules - astonishing that you can even guess the code for ones you don't have access to :http://hackaday.com/2010/03/10/50mhz-to-100mhz-scope-conversion/#comment-129124Funnily enough google shows a hit in Tek's forum for option module eeproms in modules but the post has mysteriously disappeared....

author: EEVblog
author_rank: Unknown
timestamp: August 30, 2011, 02:15:44 pm
content: Quote from: mikeselectricstuff on August 30, 2011, 01:44:44 pmA bit surprising, but not entirely so.Tek likely don't care. The people who pay $20K+ for a scope can usually afford to buy the options, and couldn't be bothered to hack it.Totally different game to your sub $400 Rigol or your $1200 Agilent X.Dave.

author: Richard W.
author_rank: Regular Contributor
timestamp: August 30, 2011, 03:31:58 pm
content: Hello Dave,the "can device" mentioned in the teardown 16:47 is a rf relay. damn expensive GHz stuff...Richard

author: FreeThinker
author_rank: Frequent Contributor
timestamp: August 30, 2011, 03:39:22 pm
content: Any update on the USB? Seems kinda sus that both the dev board and your usbsticks had problems (not that I can afford one, just curious)

author: shadowless
author_rank: Regular Contributor
timestamp: August 30, 2011, 04:19:16 pm
content: what happened after the drop test?

author: Richard W.
author_rank: Regular Contributor
timestamp: August 30, 2011, 05:06:05 pm
content: look at his face@Dave: is there any "behind the scenes footage" of the drop test?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 30, 2011, 05:16:51 pm
content: I'm sure there was something soft on the floor, like a baby, or a basket of kittens...

author: Richard W.
author_rank: Regular Contributor
timestamp: August 30, 2011, 05:37:54 pm
content: Quote from: mikeselectricstuffProbably yes, when i saw the video i expected a more splintering-crashing sound...

author: Bren
author_rank: Contributor
timestamp: August 30, 2011, 05:40:22 pm
content: Well, after watching the videos and reviews, I'm finding it increasingly difficult to figure out how this new scope will compete with the Agilent DSOX series (obviously the scope is in another league).It looks like tek has once again ignored a large part of the market, the "average joe working in his garage", leaving him to options available from tektronix that are about 20 years past it's prime (maybe a bit of an exaggeration but the technology of the TDS scope series is ancient). This puts Agilent in a very good position for future sales, they have almostNocompetition from any company within it's caliber (I'm talking large trustworthy scope manufacturers, not the cheap "take a chance on china" stuff).Correct me if I'm wrong, but I think if companies are willing to spend $20K on a device, they are either going to spend it on a really good spectrum analyzer, or on a really good oscilloscope. Not likely they would spend it on a mediocre combination of both. No?

author: aghp
author_rank: Regular Contributor
timestamp: August 30, 2011, 06:22:38 pm
content: Nice rewiev. Also I like these "teardowns".

author: Neilm
author_rank: Super Contributor
timestamp: August 30, 2011, 06:53:42 pm
content: Dave,Are the Prom keys compatible with other TEK scopes? At work we have a couple of tek scopes and we move the Proms between scopes as required (some scopes are fixed in equipment).Also there are good reasons for having the standby LED - will be useful for project Sagan when nightlights are requiredNeil

author: bogdan546
author_rank: Contributor
timestamp: August 30, 2011, 07:25:59 pm
content: Review on an oscilloscope Rhode and Schwartz would be interesting

author: ciccio
author_rank: Frequent Contributor
timestamp: August 30, 2011, 08:19:59 pm
content: I' did not find the thread in the forum, so I've posted this same question as a blog comment.Sorry for the "dual" post.Thanks for showing such a brilliant engineering work.The golden plated surface of the external layer of the RF PCB is full with maybe thousand round “holes” or vias or dimples or whatever they are. I cannot see clearly, but I’ve never seen something like.Anybody out there may explain me what they are and what is their purpose?After replaying the video, I'm pretty sure that they are vias from the upper ground plane to some other ground plane on one of the inner layers.I See that some are completely gold plated, eve the hole bottom, so I think they can be blind vias from upper layer to one internal layer, whilst other have a dark center, so the can be vias from upper layer to lower external layer, but this is what I suppose, not sure of it....How many layers have the boards? Sometimes there are some indications printed on the PCB.Thanks and regards

author: oPossum
author_rank: Super Contributor
timestamp: August 30, 2011, 10:16:25 pm
content: The four holes on the back are probably for a 100 mmVESA video monitor mount.Very common on computer monitors and some LCD TVs. Allows for the use of fancy articulated arms, adjustable stands, and wall mounts.

author: EEVblog
author_rank: Unknown
timestamp: August 30, 2011, 11:21:29 pm
content: Quote from: Bren on August 30, 2011, 05:40:22 pmIt's not designed to compete with it, they went for a different direction.QuoteYes, at the moment it does seem as if Agilent has the low to mid end market all to itself.Not the "ultra low end" of course.QuoteThe thing is it's an incredibly powerful combination, and that is very enticing.Sure, you can get better performance (apart from capture bandwidth?) in other dedicated instruments, possibly for the same money, but you don't get all the mixed domain benefits.Tek have a winner here, but it's not for everyone.Dave.

author: ivan747
author_rank: Super Contributor
timestamp: August 30, 2011, 11:50:14 pm
content: That thing is just awesome, end of the story.

author: joelby
author_rank: Frequent Contributor
timestamp: August 31, 2011, 02:26:27 am
content: I haven't watched the teardown yet, but with regard to the standby power, perhaps the spectrum analyser's OCXO is kept warmed up at all times? Pretty much all of the RF bench test equipment I've used seems to do this.

author: Unknown
author_rank: Unknown
timestamp: August 31, 2011, 02:59:05 am
content: Dave, thank you very much for the review. We can see that you put much effort in it. It is a relief to see that you maintained your critical eye and your integrity. Maybe it was hard to do so but you don't show it. Congratulations for throwing it onto the floor - my favorite part. I wish you did it in the beginning but that would have ruined the suspense. As always, superb job.As for the scope, the idea of putting spectrum analyzer and oscilloscope can not be new for the simple reason that even I thought about it. So the idea was there but it was probably suppressed by some management dweebs...for some 10 to 20 years at least. Don't tell me the technology was not sufficient, I won't buy it.For all this time, one should think, they could at least have sorted out their user interfaces. Which they did actually....in the 70's.Only they ruined it again with the advent of "the digital". Seriously guys, have you ever seen anything that runs software and has good user interface, it seems mutually exclusive. It is obvious, white men can't dance - software guys can't do user interface. You should notice that hardware people don't call it user interface. They call it simply "the controls" this implies that they are able to control it. The term "user interface" itself seems like the software people's excuse for lack of control-ability, so an interface to fiddle with it instead. Perhaps they take the task too lightly. Perhaps because they think it is of no consequence, which it is, when you think so.This scope is no exception, the user interface is slow and underpowered. Probably the engineers were rushed to get it out of the door too quick. Also one chip was missing, maybe because the bean counters downsized it.My conclusions:- I would never spend my own money on this thing.- If I was given one for free I would sell it and get something more sensible...and buy a car with the change.- If I was required to spec out a scope for my company it better be a cheaper scope....or somebody else doin' the deed.There...I feel better now.

author: EEVblog
author_rank: Unknown
timestamp: August 31, 2011, 03:48:17 am
content: Quote from: HAL-42b on August 31, 2011, 02:59:05 amNot hard at all, that's what I do, I don't know how to do anything else.Is there any reason you thought I wouldn't maintain my integrity? It's not like I get paid to do this (well, ok, it is my full time job now, but that would be the case if I did reviews or not), I do the reviews because I like doing them, and I get to play with a new toy.And of course I know *exactly* what Tektronix wanted from this review, as do all companies who ask me to review products - they want free marketing in this new "social media" space, and they wanted a video they can use as a huge marketing tool. They were hoping I wouldn't say anything bad about it, and it would be a glowing review they they can market to the hilt. Although they all grudgingly accept my "you get no say in anything" review rules, they all hope they'll get that penultimate marketing gold mine video that's all roses.In the end, I couldn't care less what they want, I make the rules, and I play with the thing and I give my off-the-cuff impression.I was disappointed by the rather lackluster performance of it, so I ranted a fair bit about that. Same with the price and comparison to Agilent etc. But I loved the mixed domain stuff, so raved about that. I bet they hate I mentioned or showed the Agilent at all, but too bad, that's a natural thing I wanted to doIn the end you get a balanced review I hope.The Agilent reviews came out more positive because there were simply less annoying or disappointing things for me to rant about.Agilent were infinitely smarter than Tek though, they let me keep it so it took pride of place on my shelf, and now gets in almost every video for years to come, offering untold ROI.Tek will pay millions in full page traditional media ads that are gone in the flick of a pageGossen were the first to see the value right back the start of the blog, giving me those meters early on in the hope they get in my videos.I do like my job, it's fun!Dave.

author: Unknown
author_rank: Unknown
timestamp: August 31, 2011, 04:34:12 am
content: Quote from: EEVblog on August 31, 2011, 03:48:17 amI thought Tek would test you, never thought you would not pass the test. I guess it angered me that you should come under such a test. But as you say that's the way you want it.Naturally Tek knew all too well that their stock had flaws, they knew exactly where these flaws were, probably they introduced some of these flaws deliberately, yet they sent it to you. Now I expect some pointy haired Tek guy to get very pissed at his UI people. It is very sad that his UI people can not fire him.

author: joelby
author_rank: Frequent Contributor
timestamp: August 31, 2011, 04:57:51 am
content: I have a TDS 744A here (circa 2001?) and its UI is somewhat similar and also ponderously slow. It's probably a flaw in their operating system or GUI library that they've never seen fit to fix.What makes you think that they would deliberately make it this slow?

author: EEVblog
author_rank: Unknown
timestamp: August 31, 2011, 05:10:22 am
content: Quote from: joelby on August 31, 2011, 04:57:51 amI agree.It's not deliberately slow, they just haven't cared enough to fix it I guess, or thought it was a major priority.Most of their scopes seem to be based on quite old architecture in one way or another (the TDS2000 is a classic example).Agilent clearly have spent many years thinking about it and investing in new ASIC technology that makes their scopes cheaper and more powerful at the same time.They seemed to have sown the seeds quite some time back and now it's reaping the rewards for them. I think they advertise themselves now as the "fasting growing oscilloscope vendor in the world"?Tek have seemed to focus on milking their existing platforms as far as they will go, and it might just cost them in the long run. But they certainly have one up on Agilent and the rest with this Mixed Domain stuff. And given that they are busy promoting that is had 26 new patents or whatever, I suspect they won't let others on the "Mixed domain" concept without a big legal fight.Dave.

author: Unknown
author_rank: Unknown
timestamp: August 31, 2011, 05:22:06 am
content: Quote from: joelby on August 31, 2011, 04:57:51 amThat chip that they left out. It probably solved this exact problem. They designed it with the chip, then omitted it, reintroducing the problem. We will probably see that chip in the next model.

author: joelby
author_rank: Frequent Contributor
timestamp: August 31, 2011, 06:09:37 am
content: Quote from: HAL-42b on August 31, 2011, 05:22:06 amThis argument makes no sense at all. If they could easily fix it, they would have because these problems are going to be just as annoying to Tektronix employees. The only logical conclusion is that the problem is too hard to solve without significant re-engineering that they don't have the time, money or expertise for, or they're at the mercy of a third-party OS vendor with similar restrictions.

author: EEVblog
author_rank: Unknown
timestamp: August 31, 2011, 06:45:32 am
content: In the case of the MDO4000, there are no fundamental improvements at all over the DPO/MSO4000 series scope which came out in Feb 2006:http://www2.tek.com/cmswpt/prdetails.lotr?ct=PR&cs=nwr&ci=3740&lc=ENSure, there has been the new "B" series, but that only improved the memory depth and front end and added extra options:http://www.pressreleasepoint.com/tektronix-introduces-new-oscilloscope-platform-breakthrough-price-performanceSo we are talking about a 5 1/2 year old platform here!Dave.

author: ejeffrey
author_rank: Super Contributor
timestamp: August 31, 2011, 07:57:30 am
content: Quote from: HAL-42b on August 31, 2011, 02:59:05 amThe technology to build a spectrum analyzer into a oscilloscope is not new, and in fact in the bad old days spectrum analyzers used oscilloscopes as their display. I admit I was less than impressed by tek's teaser announcement for this reason -- simply putting two instruments in one case tends to do a disservice to both. You can see that on this unit: the front panel controls are rather cramped, and it really does *look* like they just bolted a spectrum analyzer on, and poorly at that.However, the technology to do what Tek has here is relatively new. A swept-oscillator spectrum analyzer would be a pretty useless addition to a scope. It takes something with the 1 GHz real-time bandwidth and deep memory to get a useful side-by-side display, and a fair bit of processing to get RF triggers for the scope side. And of course it takes actually implementing the cross domain stuff so that you get something better than the two instruments side-by-side.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 31, 2011, 10:28:54 am
content: There is no excuse for slow UIs these days - CPU power is a negligible cost. Obviously this scope is based on old hardware that they didn't see fit to improve. Maybe they should hire a video game programmer to optimise the code - these people are good at getting maximum realtime response in graphics systems.

author: saturation
author_rank: Super Contributor
timestamp: August 31, 2011, 02:26:57 pm
content: A bit of good news when such scopes end up on eBay, small labs can squeeze more out of them for cheap.Quote from: EEVblog on August 30, 2011, 02:15:44 pm

author: saturation
author_rank: Super Contributor
timestamp: August 31, 2011, 02:45:14 pm
content: When it comes to equipment reviews, Dave has, AFAIK, no peer on the net. Kudos to a superb review. I particularly like the 1080p versions available because the details are so good, i don't need the static images and can run the video frame by frame to inspect the board, plus better views in the background of equipment you reviewed in the past at lower resolution.The SA board was, in your words, pure RF porn, it has such a sci-fi feel to its look.It a beautiful and well engineered tool but having the Agilent to contrast is priceless, [ I doubt we'll ever see anyone with equipment that new or costly online or with the engineering and presentation skills], but I bet the faults of the Tek would be subdued if the price were much lower than $30k. Would anyone pay $10k for it, or $5k? Suddenly UI issues are less pressing and feature set stands up higher.I do agree the dongle based upgrade is problematic, but given its easy potential for hacking, the good side is I'd be more inclined to crack it than pay for the upgradeAs for comparing the legacy of Tek in the scope market against Agilent, we all should consider its not the brand that makes the scope, but the engineering team behind it. The Tek everyone respects was from the golden days of T&M makers, when HP was still run by Bill & Dave. The Tek of today is a different beast, so one has to weigh the name less than what's underneath. The scope market thus, is open season for anyone with the guts to come up with a bang for buck, including the Chinese labels, as we are seeing from the local champions on other scopes on eevblog by tinhead and marmad.

author: sdscotto
author_rank: Contributor
timestamp: August 31, 2011, 05:39:32 pm
content: While I applaud a new product from Tektronix, I refuse to give them any of my business based on their performance over the last few years. (Danaher?http://www.glassdoor.com/Reviews/Tektronix-Reviews-E643.htm)In the old days they would go out of their way to solve a problem. If they couldn't solve it right away, they'd help with a workaround while it was being fixed.Now they go out of their way to ignore problems, make excuses, and alienate the people who were loyal and supportive.I wonder if a $30k price point product gives you any better support than a $5k or $15k product? If not, count on finding all of your own workarounds to the list of bugs you'll find.

author: EEVblog
author_rank: Unknown
timestamp: September 01, 2011, 01:25:05 am
content: Quote from: saturation on August 31, 2011, 02:45:14 pmThanks. With the new camera that is capable of so much goodness, I'm going to try harder to get the best shots I can and spend the time rendering and uploading high quality video. I think it's ultimately worth it.QuoteFor sure, all sins are forgotten for a price. That's why the Rigol has dominated the low end for several years now, so much bang-per-buck.Classic case is the Agilent OLED meter. I got hammered for recommending it (for certain people), but once the Grainger fire sale happened at 1/5th it's price, everyone bought one and started raving about it.Dave.

author: Zad
author_rank: Super Contributor
timestamp: September 01, 2011, 07:12:41 pm
content: Did you take any stills photos of the RF section? The video is good, but I'd love to see some high res stills of the layout. There is some serious RF porn in there!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 01, 2011, 08:44:59 pm
content: Quote from: Zad on September 01, 2011, 07:12:41 pmTek should do colour wall posters of it...

author: Zad
author_rank: Super Contributor
timestamp: September 01, 2011, 09:54:54 pm
content: I think I saw at least one 13-pole filter. Most common design software stops around 5 or 7 poles. It looks like they are using the Analog Devices ADF4350 as the main IF oscillator:http://www.analog.com/en/rfif-components/pll-synthesizersvcos/adf4350/products/product.htmlAs an aside, the Fox oscillators don't have a great reputation for low jitter, I am surprised they didn't use something a bit cleaner.

author: tinhead
author_rank: Super Contributor
timestamp: September 01, 2011, 10:25:38 pm
content: Quote from: Zad on September 01, 2011, 09:54:54 pmFox Xpresso?

author: Zad
author_rank: Super Contributor
timestamp: September 02, 2011, 02:05:42 am
content: Quote from: tinhead on September 01, 2011, 10:25:38 pmFox are quoting 1pS jitter 12kHz-20MHz vs Valpey-Fisher's 0.2-0.5pS. The phase noise plots seem to reflect this performance difference too. On the Fox (non Xpresso) oscillators I tested a couple of years ago, the jitter was well outside the stated figures.Talking of frequency sources, I am surprised that Tek didn't add a signal generator. Even if it weren't the same level of complexity as the Agilent's, a sweep RF signal generator would be great for filter characterisation.

author: joelby
author_rank: Frequent Contributor
timestamp: September 02, 2011, 02:07:36 am
content: Quote from: Zad on September 02, 2011, 02:05:42 amYes, it's a pity there is no tracking generator.

author: Joshua
author_rank: Regular Contributor
timestamp: September 02, 2011, 02:59:40 am
content: Dave, why did you decide to wear your wrist strap during the tear-down? I thought that was 'part of your test...to see if it survives'....Also, haven't made it all the way through the review yet, so forgive me if you already answered this, but is Tek letting you keep this scope?

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2011, 04:53:52 am
content: Quote from: Zad on September 01, 2011, 07:12:41 pmI did indeed.They will be up on my Flickr account shortly.Dave.

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2011, 04:55:41 am
content: Quote from: Joshua on September 02, 2011, 02:59:40 amAs with everything, it's at my discretion.Sometimes I do, sometimes I don't, this time I did.QuoteNo.Dave.

author: firewalker
author_rank: Super Contributor
timestamp: September 02, 2011, 09:04:24 am
content: Quote from: EEVblog on September 02, 2011, 04:55:41 amDave, about the USB. There was two usb plugs? Did you tried to connect them both.Is the any other info about the OS (apart the embedded Linux). Is it real time? I will try to find some sources.Alexander.

author: EEVblog
author_rank: Unknown
timestamp: September 02, 2011, 12:30:58 pm
content: Photos are up:http://www.flickr.com/photos/eevblog/sets/72157627575639540/andhttp://www.flickr.com/photos/eevblog/sets/72157627449876285/Dave.

author: w2aew
author_rank: Super Contributor
timestamp: September 02, 2011, 02:05:45 pm
content: Nice review Dave. It really is an awesome instrument. A couple of notes:- The scope can actually house four of the application modules (two sit behind the two that are visible up front).- More importantly, the licenses can be transferred from the module to the scope, thus allowing you to have more than four licenses installed simultaneously. In fact, all of the available licenses can be installed simultaneously.- On the RF vs. Time traces - the trace selection works just like the physical channel buttons. The "first" push will select the trace (to move the cursors to that trace for example), and then the second push will remove it. It's the same mode of operation for the channel buttons, the math button, bus buttons, etc.- To be fair, some of the update speed comparisons were done with some measurements turned on, and the Search/Mark feature turned on - both of which require additional processing on each acquisition.- The demo board comes with a USB cable with two plugs on it. If you plug them both into the USB ports on the scope (front or back), then the board powers up just fine.73,Alan W2AEW

author: Unknown
author_rank: Unknown
timestamp: September 02, 2011, 02:36:02 pm
content: I think it was a fair speed comparison. Turning Measurements and Search active on the Agilent X-Series still makes its interface snappy. There are software-processed items in the X-Series that is slow (e.g. FFT), but Dave's comparison is mainly on ones with huge contrast. Having said that, it almost covers the entire interface. I've used both scopes before, so I know myself. Once you tasted the speed, there's no going back. This is true with any other product.Other than the revolutionary RF thing, there's nothing much to yearn for. They should have polished their interface (like Dave said) for this one and charge even more. They should have plenty of time for this ... I guess they just don't care anymore (like one of the forumers said).

author: tesla500
author_rank: Regular Contributor
timestamp: September 02, 2011, 04:56:05 pm
content: Awhile back user allanw posted some pictures of a DPO4034, it's interesting to see how that's different from this onehttps://www.eevblog.com/forum/index.php?topic=1773.0http://picasaweb.google.com/113939095023945686646/TektronixDPO4034?authkey=Gv1sRgCLDw-ZCnsqCdkgEIn the DPO4034, they're using a lot of off the shelf components, a Stratix FPGA and AMCC PPC440EP applications processor. They probably use a similar processor in the MDO.The most interesting thing is the ATI Mobility Radeon GPU. I bet the big chip in the MDO is also an ATI GPU. They're probably using the parallel processing capabilities to build the graded intensity waveform display and do math/waveform processing, but I suspect the performance isn't as good as Agilent's ASICs, hence why this scope's update rate isn't as good. Also of note is that the clock speed of the PPC440 is either the same or faster than the CPU in the Agilent X series, yet the Agilent is much more responsive. Must be either careless programming on Tek's part, or limitations due to using the GPU for waveform processing. Heck, even the old Agilent 5462x series from the mid 90s were as responsive as the new Agilent stuff, using a 14MHz processor!That spectrum analyzer teadrown is absolute porn!User Carlos posted a great description of the spectrum analyzer in the eevblog.com comments:Quote from: Carlos

author: saturation
author_rank: Super Contributor
timestamp: September 02, 2011, 06:33:02 pm
content: Speaking of this, either there is a stripped USB implementation or there is a fault in the USB port of the scope. As Dave couldn't get enough power out of it to drive the test board nor power some other USB memory sticks, this suggests its configured for a very early version of USB 2.x or has a fault, and can't provide enough current to run larger cards or firmware to address large memory blocks.[quote ]Dave, about the USB. There was two usb plugs? Did you tried to connect them both.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 02, 2011, 07:37:38 pm
content: Quote from: saturation on September 02, 2011, 06:33:02 pmThat board looks like it probably wants more then 100mA, which is the minimum a USB port must provide - 500mA is available by negotiation, and probably not required for the sorts of things you'd normally stick in a scope host port - my guess is the eval board came after they'd specced the USB current limit - may be a hangover from the old DPO4000 design.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: September 02, 2011, 08:17:59 pm
content: Yes but $20k+ for a scope with flakey Usb?. Either they are faulty and need sorting or they are badly specced and need sorting But it needs a good coat of looking at before they batch any more! Yes?

author: IanB
author_rank: Super Contributor
timestamp: September 03, 2011, 01:44:58 am
content: Quote from: mikeselectricstuff on September 02, 2011, 07:37:38 pmAre there any USB ports these days that can't supply 500 mA? Especially on devices with ample on-board power?I really don't think there is any excuse for restricted current. It would seem like a major goof-up.As Dave observes in the review, it seems like the marketing department have grafted on this spectrum analyzer feature for feature points in the sales literature, but they have not allowed the engineers to improve the basic design of the oscilloscope in a way that would make it appealing to the engineering types who might want to use it as a practical working tool. It's a cool idea badly executed.

author: Zad
author_rank: Super Contributor
timestamp: September 03, 2011, 01:54:27 am
content: Thanks for the photos Dave!

author: EEVblog
author_rank: Unknown
timestamp: September 03, 2011, 03:22:47 am
content: Quote from: tesla500 on September 02, 2011, 04:56:05 pmI used to have a 54621D and it was a great scope, and was certainly as responsive as anything going today.Dave.

author: EEVblog
author_rank: Unknown
timestamp: September 03, 2011, 03:24:32 am
content: Quote from: IanB on September 03, 2011, 01:44:58 amI agree, it's a goof-up, and having to plug in both to make it work is a kludge.Dave.

author: Thomas
author_rank: Regular Contributor
timestamp: September 03, 2011, 04:31:11 pm
content: I think the two USB connectors are there for a reason: it needs more power than can be provided from one USB port.Seen it on some external HDD's and some instruments.

author: ejeffrey
author_rank: Super Contributor
timestamp: September 03, 2011, 05:16:45 pm
content: Quote from: IanB on September 03, 2011, 01:44:58 amThe only common case is bus powered USB hubs (including those built in to peripherals like keyboards). Since USB requires power negotiation, it the failure is probably not actually inability to provide sufficient current, but that it is not negotiating correctly. My WAG would be that their USB controller didn't support as many ports as they wanted so they threw an off-the-shelf USB hub chip in but forgot to to wire the pin (or whatever) to tell the hub controller there is external power available.However, this doesn't really explain the problem with the USB flash drives which I thought were usually low power devices. Maybe that is a separate issue with the filesystem driver.

author: EEVblog
author_rank: Unknown
timestamp: September 03, 2011, 11:59:25 pm
content: Quote from: Thomas on September 03, 2011, 04:31:11 pmI haven't measured it, but it works fine on just one USB port on the Agilent scope, and every other USB port I try that can supply the usual 500mA (the "negotiation" requirement is a misinterpreted myth).Tek put in wimpy USB power, and my guess is they realised it after the fact, so provided the split USB cable.Dave.

author: jahonen
author_rank: Super Contributor
timestamp: September 04, 2011, 07:13:58 am
content: Quote from: EEVblog on September 03, 2011, 11:59:25 pmWhat myth, the USB 2.0 specification is quite clear on that point (unit load = 100 mA).I personally hate those ignorant "just ignore the spec, it'll work fine" guys. I know the negotiation is a PITA on simple devices but it is the only way to guarantee interoperability. While most hobbyists do not care but I'd expect that at least Tek guys wouldn't be so ignorant.QuoteandQuoteI think the present situation is due that most host devices have no proper power management. I know that my friend once smoked usb cable of his camera when the camera end connector shorted out. So much for even 500 mA current limit. Probably the motherboard did not contain any kind of current limiting, thus passing through all what was available on the PC PSU.Regards,Janne

author: Bored@Work
author_rank: Super Contributor
timestamp: September 04, 2011, 07:32:31 am
content: Quote from: EEVblog on September 03, 2011, 11:59:25 pmThen explain what the USB standard, Revision 2.0, April 27, 2000 means in section 7.2, especially section 7.2.1. and 7.2.1.4. Lets just take a look at parts of them:QuoteQuoteThe requirement is not a myth, it is a reality. Completely in the open for everyone who cares to read the USB standard.Which is the point "cares to read the USB standard". The problem are developers running around, designing USB devices and giving a toss about the USB standard, declaring requirements of it a myth, while they haven't read a single line of the standard.Most device designers give a toss, and use as much power they dammed like, and most host designers have bend over and just supply whatever power the host wants until the USB host chip goes up in flames. But that doesn't change the requirements in the standard. The requirements are real.And the requirements can be summarized as 0 mA on bus suspension and 100 mA max. on device power up. Then the device specifies its requirement in the bMaxPower field in the configuration descriptor, and gets the required power granted with a Set config or denied.But yes, it is more convenient running around and wanking over a "weak" USB host port. The truth is, you know nothing about the port. You would need a logic analyses with USB decoder and current measurement to figure out what is really going on. Does the device board properly enumerate? Does it properly not use more than 100 mA at start? Does it properly specify its required power in bMaxPower in its device configuration descriptor? Does the host grant that power?Without having done those measurements you know nothing, especially not if it is the oscilloscope's or the board's fault. And don't give me that "I have 20 years of experience", or "everyone does it". Read the standard, measure, compare the results against the standard and then we are talking. Not that childish "they designed a weak port". Maybe they did. But you don't know.

author: Bored@Work
author_rank: Super Contributor
timestamp: September 04, 2011, 07:37:27 am
content: Quote from: jahonen on September 04, 2011, 07:13:58 amGood to see I am not the only person in the world who has read the USB standard.

author: ejeffrey
author_rank: Super Contributor
timestamp: September 04, 2011, 08:43:11 am
content: Quote from: EEVblog on September 03, 2011, 11:59:25 pmIt is not a myth, although it is often misinterpreted. It is true that USB ports almost never have programmable current limiting. If you attach a 10 ohm resistor across the power pins of a standard USB port, you are going to get 500 milliamps of current but be in violation of the spec. To be in compliance you must request high power mode. If you do not, there is every chance that not only will your device fail to work when plugged into a bus-powered hub, but you take down other devices plugged into the same hub. There is really no excuse to not do proper USB power negotiation.If the demo board is operating correctly it will power up the microcontroller on insertion, then only power on the rest of the circuitry after requesting high-power mode from the host. This is why I think it is more likely solution is not that the 5V rail is underpowered, but the host is failing to negotiate high power devices.On the other hand, it is certainly possible that they put an underpowered regulator on the USB5. It is even possibly they advertise high power capability but don't actually have a beefy enough supply to support it. I kind of doubt this it is easier to screw up the protocol than the power supply.

author: EEVblog
author_rank: Unknown
timestamp: September 04, 2011, 09:24:20 am
content: QuoteAnd that is exactly what I am talking about.I'm not talking about the proper design of USB devices, I'm talking ONLY about the USB ports ability to supply 500mA.The common "myth" I referred to is that a USB port will ONLY supply 100mA max UNTIL an intelligent device requests more.AFAIK, that is NOT the case. A USB port will be able to supply the 500mA, and they do, without negotiation.Talk about proper USB device design is an entirely different issue, and you won't get any argument from me.Dave.

author: ejeffrey
author_rank: Super Contributor
timestamp: September 04, 2011, 09:28:05 am
content: Maybe you could hook your constant current load up to the USB power pins and see how much you can draw before it starts to drop out? That would answer the question whether it was a protocol issue or a power supply issue.

author: EEVblog
author_rank: Unknown
timestamp: September 04, 2011, 10:30:30 am
content: Quote from: ejeffrey on September 04, 2011, 09:28:05 amOk, I went and did some measurements, mystery solved.The demo board draws around 850mA, so clearly is not designed to be operated from a single USB port, hence the dual plug supplied. The red "power only" plug is included to get the extra power from two paralleled ports, and not to simply power the device without any comms as I had assumed.The Tek USB port on the front can supply up to around 800mA before the protection circuit kicks in (probably lower if left longer), hence the hiccuping observed. All the other USB ports I used were obviously able to supply that 850mA without the protection circuit kicking in, hence the confusion and my assumption that the board was taking 500mA max.So the Tek ports aren't "weak" as I lead to suspect.Dave.

author: EEVblog
author_rank: Unknown
timestamp: September 04, 2011, 10:37:11 am
content: For those interested, Iiro Sundberg emailed me an attempt at a system description of the RF section, with labels overlayed on an image of the board:Quote

author: ejeffrey
author_rank: Super Contributor
timestamp: September 04, 2011, 01:38:47 pm
content: Quote from: EEVblog on September 04, 2011, 10:37:11 amNice!

author: Chasm
author_rank: Regular Contributor
timestamp: September 05, 2011, 01:17:06 am
content: Quote from: EEVblog on August 31, 2011, 03:48:17 amI suppose that Tek would rather give the scope to someone who actually does RF work.So, are there any ham related video podcasts out there? If not it may be high time to start one. Maybe yet another project for Chris?

author: metalphreak
author_rank: Frequent Contributor
timestamp: September 05, 2011, 02:23:36 pm
content: Every modern PC motherboard i've looked at, has the USB power pins connected directly to the systems 5V power rail, with protection in the form of a 1A surface mount PTC fuse. Its almost always 1 PTC per 2 USB ports, so 500mA each. It's really only meant for short circuit protection, but this means you can easily draw more than 500mA from a PC's USB port. Many older PCs had no current limiting protection, and a dead short meant a fried motherboard. It's up to the device to conform to specs and tell the PC what its drawing.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: October 14, 2011, 11:27:23 pm
content: That's a rough statement, 'most modern boards.' I know from experience that my MBP (notorious for lower-power USB ports, more like 550 mA than 850) gets VERY mad when you overcurrent it. The OS complains, that USB host shuts down, won't come on till proper data negotiation...

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 30, 2013, 01:57:20 am
content: Well, is it true that Tektronix hasn't introduced any new scope since this in 2011??Except for the funny "new" TBS1000 series...

author: EEVblog
author_rank: Unknown
timestamp: May 30, 2013, 02:29:13 am
content: Quote from: Hydrawerk on May 30, 2013, 01:57:20 amYes, it's true. And nobody expects them too any time soon.The "Dananher System" probably has the R&D team (what's left of them) by the short and curlies.

author: w2aew
author_rank: Super Contributor
timestamp: May 30, 2013, 03:39:30 am
content: Quote from: EEVblog on May 30, 2013, 02:29:13 amNot really true. A few additions to the MDO4000 series were introduced several months ago, a new DSA8300 sampling platform was introduced last year, and there were two ultra-performance scopes introduced recently at 25 and 33GHz bandwidth (100GS/s). Nothing really new on the low end, but I'm sure that will change in the future.In addition to that, there have been two new RSA5100A series real-time spectrum analyzers (15 and 26.5GHz), and a pair of new Arbitrary Waveform Generators (2ch @ 25GS/s and 1ch @ 50GS/s), all introduced this year.

author: EEVblog
author_rank: Unknown
timestamp: May 30, 2013, 04:05:14 am
content: Quote from: w2aew on May 30, 2013, 03:39:30 amA new low end Tek scope, the Lochness monster of the T&M world!

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 30, 2013, 09:05:03 am
content: Quote from: w2aew on May 30, 2013, 03:39:30 amYes, but I'm not sure that will help Tek much. The DSO/DSA700000 competes with Agilent's DSOX9000Q and LeCroy's LabMaster 9Zi/10Zi, which offer higher sampling rates (120/160GSa/s, and the LeCroy even does that on all channels), and all are available with higher bandwidths than Tek offers as well. Considering that the Tek isn't even cheaper than Agilent and LeCroy, there is probably very little reason to go with Tek nowadays.Dave is completely right with his comments re. Danaher. Their 'Danaher Business System' (DBS) is focused on shareholder value and micromanagement, and offers very little room for creativity or taking risks (which is what most new technologies are). The result is a Tek that is constantly behind the curve and outperformed by its competition. Their offerings are depressing, and it seems their sales staff is aware of that as they have become much more active recently (I never got so many calls from our Tek representatives trying to get some business).I grew up with a lab full of Tek, but nowadays I would not even consider them anymore, neither for a low end scope and even less for a high end scope.

author: EEVblog
author_rank: Unknown
timestamp: May 30, 2013, 09:31:06 am
content: It should also be pointed out that even the Tek MDO4000 is in essence not a new scope. Sure it's got the awesome MDO capability essentially bolted on, and that was a genuine innovation. But as for the scope part itself, how old is that architecture? IIRC, they have tweaked it a few times with faster memory and processor, but it's still a very old design.And it is as slow as a wet week because of that, and Tek did not like that I said that, but I have yet to hear anyone outside of Tek disagree with my review of that scope.When was the last time Tek genuinely made a big advance in their low or mid range scopes?The TBS scope seriously turned Tek into a laughing stock.I hope they something in the works, I really do...

author: Bored@Work
author_rank: Super Contributor
timestamp: May 30, 2013, 10:05:32 am
content: Quote from: EEVblog on May 30, 2013, 09:31:06 amI would have loved to be on the fly when that phone call came.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 30, 2013, 03:28:25 pm
content: In 1998, this must have been a great scope.I think that in early 2000 Agilent didn't have any compact "non-deep" scope...And yes, maybe Tektronix offers better (and bloody expensive) active probes. But that's not interesting for a hobbyists.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 30, 2013, 03:29:38 pm
content: What the fuck is this... This is not a MSO2000 or DPO2000 scope!!

author: ddavidebor
author_rank: Super Contributor
timestamp: May 30, 2013, 03:35:59 pm
content: I've tried some funky 10k€+ tek...and they're look and feel like the one with the floppy in my school.Pretty depressing thing...

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 30, 2013, 03:47:51 pm
content: As someone said, Tektronix is doing some advertising...Another crap video. The memory of Agilent DSOX2000 is not shared between channels, it has 100kpoints per channel and you can even buy an extension to 1Mpoints per channel.On the other hand, I love the Wave Inspector dual knob...

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 30, 2013, 03:52:14 pm
content: What's this? Tek guys wanted the DSOX2000 screen look smaller??And how did the white strip get there??It never appeared on my scope's screen.

author: MarkL
author_rank: Unknown
timestamp: June 08, 2013, 03:31:26 pm
content: Quote from: Hydrawerk on May 30, 2013, 03:52:14 pmThat white strip is added to the image when you do a screen capture.Perhaps a little cut & paste to make this "photo"? Oops.

author: Hydrawerk
author_rank: Super Contributor
timestamp: June 08, 2013, 03:58:03 pm
content: Quote from: MarkL on June 08, 2013, 03:31:26 pmYes, I know, but it's never shown on the scope's screen.