O'scopes - Tek vs HP/Agilent vs LeCroy

If you have reps nearby, see if you can borrow one of the LeCroy scopes. I had a demo of one a few years ago and it was a very nice scope. I've used old LeCroy scopes out of the late 80's and mid 90's. They were pretty decent scopes until you blow up a front-end module. Only thing I didn't like about the newer (2004) LeCroy scope I saw: runs under Windows. Back then, they suggested installing anti-virus software!

I like the mixed signal oscilloscopes from HP. Loads of memory and not very difficult to use. Never had problems with the trigger.

These days most oscilloscopes run Windows. As long as you don't connect them to a network directly, you'll be fine.

The problem with the older Lecroys is that they don't have peak detection. At lower sampling rates, you won't see the spikes so you have no clue on what signal is present.

If you want deep memory, Tek doesn't seem to have any great offerings (at least in the less-than-a-car price range I was looking in). They

The HP/Agilent mixed signal stuff has deep buffers, but the sample rates on the scope side are very low. A 100MHz digital scope from Tek is 1GS. A 100MHz Agilent mixed signal scope (546xx series) is 200Ms. That also applies on the digital side. Timing mode only (no state mode) at 200Ms sounded bad to me for any bus over about 33MHz, but I never tried it myself.

Lecroy claims deep buffers and good sample rates, but I've never used one. I don't know if they really keep the deep buffering at max sample rates or with multiple channels active. They do have a loaner program which would let you try one out. Most comments I saw were about hating the UI, but you can learn any UI eventually.

We purchased a couple of DSO/MSO6104A's a few months back -- Agilent was having a sale, wihich made them quite price competitive. At 1GHz they're

Our local Tek rep was a little disappointed, but conceded that -- especially with the discounts -- they couldn't really compete. He hinted that they weren't intending to let Agilent have the entire MSO market for much longer, however.

I have a LeCroy Waverunner LT584L - it was ex-demo, and they threw in every option for free ! I've owned/used HP and Tek as well, and I think that the best summary is that different models vary widely - you need to play with an actual sample of the scope you are interested in, rather than try to predict. For instance, the Waverunner has deep memory, which is very useful for serial stuff, but they forgot to update the 'knobs' that scroll back and forth so it can take a lot of knob twiddling to get to where you want - things like that can be annoying until you find the way round.

I'm probably about to upgrade, and it will likely be an ex-demo LeCroy again - I like the interface and the discounts at this time of year are good.

When you are looking, be sure to consider and price options - if you want them added later, you will pay through the nose (and mouth and ears and ...)

I'd hesitate to buy an exotic scope on ebay - any problems and you will be much poorer. Modern scopes are effectively not serviceable.

Dave

There is no IF - you DO want deep memory.

If you have the budget then the Agilent 6000 series is well worth a look. When I was buying a 300MHz scope a year or so ago, the Agilent stood way ahead of anything else in the price range - I know Tek have introduced a range since then though so probably worth taking a serious louk at both.

For mixed analogue/digital use, the Agilent MSOs don't really have any competition - since having an MSO (the original 54645D then the MSO6034A) I've only used my logic analyser once in 12 years. Agilent will do evaluation loans for a couple of weeks so you can really give it a good try. Warning - you probably won't want to give it back afterwards...! The speed & responsiveness of the user-interface is way better than any Tek I've ever used.

I was buying a 300MHz

price range - I know Tek

louk at both.

competition - since having an

once in 12 years.

it a good try.

I've ever used.

Thanks for the comments, everyone. I'm now leaning towards a HP DSO6052 or MSO6052. Considering that I have a HP logic analyzer, what would be the benefit of a MSO vs a DSO?

-Dave Pollum

When I was buying a 300MHz

price range - I know Tek

louk at both.

competition - since having an

once in 12 years.

give it a good try.

I've ever used.

Deep memory and correlation with analogue channels. The ability to quickly instantly look at a strangely-behaving digital channel with an analogue probe. Not to mention the convenience of having it all in the same box with the same user interface. Also has handy stuff like I2C, SPI and Nth-pulse in burst triggering - some of these can be sone on a LA but can be fiddly to set up. With deep memory you need to care about triggering a lot less often as you can take a 'grab anything then zoom in' approach. I think the price difference between DSO and MSO models is the same as the price difference in the basic model - the 'upgrade' is a set of leads and a password to enable the functionality.

Get hold of a loan unit and have a play with it. You'll soon decide what you do & do not find useful.

LeCroy is evil.

John

My MSO6034 is excellent in this respect - apart from the usual stuff ( including any/both edge options) there is I2C, SPI, LIN, N'th pulse-in-burst, pulse-width, pattern, logic pattern+duration, logic sequence, TV and USB.

Although with deep memory you don't need fancy trigger modes as much as you otherwise might.

We bought a few LeCroy scopes this past spring (a couple of WaveRunners and a WavePro), chosen because of the lower price. I hate them. The user interface is terrible. They run the desktop version of Windows XP (which crashes!). LeCroy recommends you run a virus scanner on them and run windows updates -- which may or may not be incompatible with LeCroy's software (we keep them off the network, but this makes it a pain to transfer data off them for analysis). They are extremely slow to rescale or change range.

The cheaper WaveRunners, however, are better then the more expensive WavePro (although the protective layers on the screen of one of the cheaper scopes looks like it may be delaminating). The expensive WavePro was crashing constantly. Sometimes it would seem the device under test wasn't producing any signal, but it was just that the scope had crashed and wasn't updating the display! ("fixed" by a scope reboot). When the touch screen stopped working, we returned it for repair. The sales rep arranged for a loaner, faster then our 1GHz scope. It crashed, too. When ours came back from LeCroy, the only "repair" they did was to reinstall Windows! The touch screen worked for another couple of months then went out again. Now the front panel is dead. The only way to change the settings on the scope is with a mouse, going through many menus to do something as basic adjusting the timebase. It's going back for repair soon.

I can't believe anyone would sell a scope that crashes. Why would you build a dedicated scope on a desktop operating system? Do you really need to browse the web or send email from your scope? Do you want to worry about your scope getting infected by the latest Windows exploit? That's just wrong. As someone said elsethread, "LeCroy is evil".

Same reason there's plenty of software out there that crashes? -- Most companies, these days, feel it's better to get the product out the door with "some amount" of testing and figure they'll issue software updates later as more bugs are found than to extensively test the software.

The problem is that "some amount of testing" can vary *greatly* between different companies.

Because it's a lot cheaper than rolling your own OS these days or using an embedded OS like VxWork or QNX? And programmers witih experience in desktop OSes are a lot easier to find? A better question would be... why didn't they use Linux, like the low-end models of their competitors do?

It can be handy to e-mail yourself data files? It is nice to be able to print to any printer that's already on your network. (But in both cases Linux does pretty well here too...)

Don't plug the machine into your network if you're worried about such things?

John just thinks Walter LeCroy is a prick. :-) I haven't heard why, although I imagine he's expounded on it at some point.

Thats one of the wildcards in the Tek UI. You can use two scopes with essentially the same knobs and buttons, and one is a pleasure to use and one is a dog. The TDS64x (I think it was) series only updates from ANY panel input between acquisitions. It's sluggish at 2500 points, but if you crank it up to 15000 points it will drive you nuts. The same feature will have radically different performance on different models. The "autoset" on my TDS2014 is a real timesaver. On some of the older models it's shorthand for "change every setting to a random value". Of course I expect an "autoset undo" softkey to save me (which newer scopes have) but there isn't one...

Joel said: "...just defending the concept of "desktop OS"-based instruments in general; it's clearly the direction things like scopes, spectrum/network analyzers, DLAs, etc. are going."

I used a late model Tek LA a few months ago for about a week. It ran Windows (2K or XP???). I powered it up in the morning and powered it off before I left for the day. It didn't take me long to figure out how to use the LA, and it became a joy to use compared to my HP 16500C LA.

Another point - if the entire instrument crashes, well that's really annoying, but the instrument should _not lie_ about the signals it's probing just because the O/S goes belly up! A non-trustworthy peice of test gear is useless - it's a huge waste of time.

-Dave Pollum

That doesn't mean it's the right direction.

So the 16500C's UI isn't as good, and the one on Windows is better. That doesn't mean that it's the best idea to run a logic analyser on Windows.

Most of the UI doesn't come so much from the OS anyway. You probably (hopefully) spend most of your time working within the analyser application. On some recent Tek models, that's actually LabVIEW. (Can they get any lazier?)

And one that crashes frequently, and requires security patches (the idea!), and spends gobs of time booting up, and uses special PC components that go obsolete in six months, and special hard drives that come in special cases so you can't repair them yourself, and so the maker can charge you ungodly parts & labour cost, is also a giant waste of time.

I hated Windows scopes when they first came out, and I still hate them now (in case you couldn't tell). Not only do they have the same Fisher-Price feel to them that regular Windows has, they have the same reliability. A workman is known by his tools.

Besides, I've already got a Windows laptop, which I have to use for work. If I have to use Windows on an instrument, I'd rather just use my laptop, which has a bigger screen, an attached keyboard, and a known set of foibles. So give me the PicoScope-type instruments any day, if Windows has to be in the mix.

--mpa

That actually makes sense for data-intensive things like logic analyzers and maybe spectrum analyzers. Scopes should have knobs and screens.

John

Data said: "So the 16500C's UI isn't as good, and the one on Windows is better. That doesn't mean that it's the best idea to run a logic analyser on Windows."

The only application I ran on that Tek LA was the Logic Analyzer. And yes, the Tek LA's GUI was much better than the HP16500C's GUI. But, don't forget the 16500C is several generations older than the Tek LA (TLA5000 series?) that I used. I'd love to get a more modern LA, but can't afford one.

-Dave Pollum.