2GHz+ Real Time Oscilloscope capable of USB 2.0 Hi-Speed Analysis - Page 1
Forum section: electronics / testgear

author: ransonjd
author_rank: Contributor
timestamp: February 02, 2018, 11:56:25 pm
content: Hi,This is a professional-use oscilloscope question, and I get that there may not be too many people who have advice for me. My old standby scope is dying (A Tek DPO2014), and I need a new scope. I'm considering an upgrade so that I can do more signal integrity work without renting equipment. What are the least expensive good modern* oscilloscopes with 2GHz bandwidth and options for USB 2.0 hi-speed signal integrity analysis? I would also like to be able to decode standard low speed serial buses, like SPI.Thanks!*New or used, but no floppy drives please.

author: DaJMasta
author_rank: Super Contributor
timestamp: February 03, 2018, 01:02:12 am
content: Floppy drives are going to be common even in more modern equipment, I've got a WavePro 7200 made in 2005 that still has one in the front panel. I believe it would be a software option for analysis on that unit, but it's got a 2GHz frontend and sample rate to spare.Something like a wavepro 960 or newer, or a DDA-260 or newer would be some of the cheapest used scopes on the LeCroy side of things. Haven't really looked into the price of Tektronix or Keysight, but I'd assume theirs are comparable if not a little higher.If you're just looking for an eye diagram, even a base scope of that performance will do the job, but if you're looking for protocol specific USB stuff or jitter analysis or whatnot, that's going to require a software option which is going to be expensive, so I'd look for it as a primary element in a used scope just because it will easily be $1000 or more to add in to one without it.Also consider the cost and availability of probes. If you're looking for something that will be good for the full bandwidth, you're easily looking at several hundred dollars per active probe, and sometimes more for a differential probe. I think tek probes have the most used availability, but again you'd probably need to used if you're keeping the cost down, a new few GHz range active probe could easily cost as much as a nice used scope...If no floppy is a requirement, that probably leaves out any Windows 2000/XP based scope and most of the cheapest options for that sort of bandwidth, I'd expect that requirement to cost you at least $1000 on the used market, though of course you're getting a more modern scope out of it.

author: ransonjd
author_rank: Contributor
timestamp: February 03, 2018, 01:18:38 am
content: No floppy isn't really a requirement, but I would like a non-floppy way of getting data off the scope. USB sticks, USB cables, or ethernet would be fine. Compact flash wouldn't be terrible. if there are firmware updates, I would like to be able to install them without a floppy.My biggest concern would be reliability: Can I expect to amortize the cost over enough years to make it more cost effective than occasional expensive rentals?Thanks!

author: Gerhard_dk4xp
author_rank: Frequent Contributor
timestamp: February 03, 2018, 02:13:56 am
content: IIRC, the Agilent 54846B is mentioned in the USB docs for acceptance tests.I've got a used one, I'm quite happy with it. Boot time could be shorterand memory somewhat deeper.regards, Gerhard

author: chriswebb
author_rank: Unknown
timestamp: February 03, 2018, 02:24:03 am
content: What kind of price range are you talking about?

author: ransonjd
author_rank: Contributor
timestamp: February 03, 2018, 03:06:40 am
content: The price range I'm looking at is sub $10k. I know that covers a lot of ground, but it depends on the value for the money.

author: Someone
author_rank: Super Contributor
timestamp: February 03, 2018, 08:56:59 am
content: Quote from: ransonjd on February 03, 2018, 03:06:40 amYou'd need to spend a lot of time hunting bargains to keep under that price, start by getting lucky with a second hand scope that already has the appropriate licenses installed/enabled and then find the matching fixtures, cables, and probing to suit.

author: ransonjd
author_rank: Contributor
timestamp: February 03, 2018, 02:32:38 pm
content: To be clear, 10k, including options, but not including probes and fixtures. I need a scope now, but I can defer accessory purchases so long as the probe interface is BNC compatible.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: February 03, 2018, 10:25:15 pm
content: I'm in a similar boat, but I'm merely looking for an upgrade, so I'm waiting for a good deal to come along. The top of my list right now is an Infiniium S-Series. It looks like the baseline DSOS054A model runs around $10k used and can be hacked without too much trouble into the top-of-the-line MSOS804A. Unfortunately $10k is a bit more than I'd like to spend so the wait continues. (Also, I'd like to snag one with at least the stock passive probes included... you can never have too many probes....)If I needed something right now, one of the older Infiniiums would be pretty tempting. Something like this oneeBay auction: #222707215246looks pretty reasonable, though I personally don't much want to deal with the older Windows installs. (No relation to that seller, haven't even read the listing thoroughly, might not be a good deal, etc.) They do have the dreaded floppy drive, but are new enough that they've got USB slots. You do get an awful lot of scope for the prices they're going for.

author: EE-digger
author_rank: Frequent Contributor
timestamp: February 04, 2018, 02:24:34 am
content: I've used the Agilent 54846A for USB 2.0 HS tests. It delivered very nice plots using the USB SIG test application. You can use a Tek or other test board to provide the proper load but I used 2 very well matched BNC cables to test points on a stripped flash drive, with proper load resistors.For serial decode and protocol, as has been mentioned you'll need something more modern and will pay for it. The software suites are not cheap. I have a DSO9254A at work and gagged when I saw what else was required. I pulled out an old TDS694C for one project and the Agilent (above) for a later project.The DSOX 3000 T has some USB testing and I think some limited decoding. The 1GHz or 1.5GHz is fine for this but not good enough for the eye patterns.If you wait a bit, you'll need to be testing USB 3.x and will then need a few hundred k$Maybe Dave would let us borrow his loaner for 3.x testing ... just for a few days eachRegarding older Windows on the Infiniiums ... don't let it scare you. The 54846A I mentioned is rock solid and is Win98SE based. I think I replaced the HD with a small SSD. I found a universal driver and it now works well on USB storage. I also have a wireless mouse and keyboard on it and life is wonderfulMemory depth is pathetic but plenty enough to get the USB sequences completed.

author: jeremy
author_rank: Super Contributor
timestamp: February 04, 2018, 03:13:20 am
content: Quote from: exmadscientist on February 03, 2018, 10:25:15 pmSource?

author: KE5FX
author_rank: Super Contributor
timestamp: February 04, 2018, 04:51:02 am
content: Quote from: ransonjd on February 02, 2018, 11:56:25 pmThe TDS 694C is probably the cheapest 3 GHz realtime scope out there, at under $2K typical. It has a floppy drive, though.And it doesn't decode SPI (or anything else)... but unless your SPI bus runs at 2 GHz+, you're probably better off buying a cheaper and much newer scope for that task.You can get plots and raw data out of it without too much trouble:My understanding is that USB 2.0 HS development is actually what the TDS 694C was originally targeted towards. It will be OK for signal integrity work at the physical layer, but if you need to capture long records or run the USB SIG validation software, it may be necessary to spend more of that $10K budget.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: February 04, 2018, 07:34:50 am
content: Quote from: jeremy on February 04, 2018, 03:13:20 amMostlythis threadbut I think a few other hits came up when I searched.I should add that one of the reasons the S-series (or other recent Infiniiums) are attractive is the possibility of using the 8GHz scope frontend to feed the VNA software (89600) and so get a "poor man's" SA in the same instrument... not that anything about a piece of hardware that lists for $73k plus $whoknows in software options can be called "poor man's", but you get the idea.

author: jeremy
author_rank: Super Contributor
timestamp: February 04, 2018, 08:04:05 am
content: I think you might be mistaken, the DSOS models are newer and very different to the DSO models in terms of the embedded system hardware. They run windows 7, and support DisplayPort and USB3 and have touchscreens and on-device matlab support and a bunch of other things. That thread refers to the DSO models only afaics.

author: nctnico
author_rank: Super Contributor
timestamp: February 04, 2018, 10:42:38 am
content: IMHO the Lecroy Wavepro 7300A could be an option. AFAIK it has decoding but no peak detect though which makes it less useful as a general purpose oscilloscope. I wouldn't buy the TDS694C. It has several issues (age, trigger chip and display) and you need special equipment + software to calibrate it. The Agilent 54846B is also nice but check it's trigger abilities. I have the related older 54845A (1.5GHz model) and that can trigger up to about 1.2GHz and the maximum bandwitdh is on 2 channels only.

author: KE5FX
author_rank: Super Contributor
timestamp: February 04, 2018, 11:31:19 am
content: Quote from: nctnico on February 04, 2018, 10:42:38 amLooks like some of the 7300As have been selling for less than $3K, too. I didn't know they were that cheap. Sounds like a great candidate for the job, since you can buy two or three of them with a $10K budget.

author: Howardlong
author_rank: Super Contributor
timestamp: February 04, 2018, 06:15:38 pm
content: While it's not a perfect solution, I use my own in-line fixture to sniff the D+/D- lines and use appropriate FET or low-z probes to take a look. Real time I max out at 1GHz, but with sampling scopes I can go up to 20GHz for eye diagrams.For decode, I use the LeCroy Mercury T2C analyser occasionally triggering between it and a 1GHz real time scope if needs be: it's a good way to look at things visually and "remove the veil" so to speak, looking at it physically. Two comments on this, firstly not all analysers provide triggering facilities, and secondly at USB HS, although it's 480Mbps signalling rate, remember it's 240MHz in frequency terms. The T2C software also provides a "waveform" of what you should see on the scope, minus any preamble, but t's of little use from a signal integrity perspective, it's just ones and zeros. It is handy to correlate with what you see on the scope though.Although the T2C has a 256MB capturing facility, at HS it doesn't take long to fill it up! Judicious filtering and triggering are key. The software for the T2C is a little hard to get your head round, it's a bit of a mess IMHO, not really obvious where you need to go to do things, so be prepared for a bit of a learning curve. It's the result of trying to pile everything including the kitchen sink into one package. I would say that the software is pretty reliable though.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: February 04, 2018, 07:48:22 pm
content: Quote from: jeremy on February 04, 2018, 08:04:05 amIt's true that the hardware is very different, but the software isn't. All the recent Infiniium releases seem to be closely related, as you'd expect from a development point of view. Post #8 (reply #7) in the linked thread suggests that the S-Series software is indeed hackable. I'm comfortable enough in my SW RE skills to give it a try, if I can find the HW at a good enough price... after all, even if I fail to unlock anything, I've still got a DSO-S