Show us your square wave

[joeqsmith]

Ok, that is fine...but Wuer said 100MB and you retyped it as 100Mb and said you didn't understand why he said that was impossible.....he didn't say 100Mb.....you misread or misquoted that....50MB on 1Gb ethernet is no problem....even on small blocks you should get somewhere around 47MB, so 50MB is totally in the realm....but 400MB on 1Gb, no way.....

I see a misquote on your end....that's why it's not adding up.  Wuer is bang on with his statement of 100MB on 1Gb ethernet....and he is being generous there. 

When you showed your data on the LeCroy forum, did you mistakenly flip those MB vs Mb figures?  If so I can see why no one responded....not trying to be rude at all, just trying to point out that those bits of terminology are pretty damn critical in making any realistic assessments

  missed that.    Makes more sense now that I reread it.  I was thinking man, 100Mb on a 1Gb connection is good?     
No problem.  Good catch.    My original post to the LeCroy forum:

A short video showing the results of adding a 1000Gb board to the Wavemaster.  I used an Intel PRO/1000 GT Ethernet board which supports off loading some of the processing that the OS would normally have to do. 

I can leave both ports attached to the switch, each with their own IP and select the card I want to use from Labview.   XStream has no problems with it.   

I ran some tests with larger MTU size, Nagle enabled, changing the DSOs software priority and direct connection to the PC rather than using the Cisco switch.   Gains were minimal.

The one thing that I do notice that is not in the video, at 20GS/s the poor DSO has no time left to service the Ethernet.   Depending on what you are doing, I have seen average data rates as poor as 10Mb-20Mb with the 100Mb port.    In all cases the add-on board yielded better performance.   

[TunerSandwich]

Ok, that is fine...but Wuer said 100MB and you retyped it as 100Mb and said you didn't understand why he said that was impossible.....he didn't say 100Mb.....you misread or misquoted that....50MB on 1Gb ethernet is no problem....even on small blocks you should get somewhere around 47MB, so 50MB is totally in the realm....but 400MB on 1Gb, no way.....

I see a misquote on your end....that's why it's not adding up.  Wuer is bang on with his statement of 100MB on 1Gb ethernet....and he is being generous there. 

When you showed your data on the LeCroy forum, did you mistakenly flip those MB vs Mb figures?  If so I can see why no one responded....not trying to be rude at all, just trying to point out that those bits of terminology are pretty damn critical in making any realistic assessments

  missed that.    Makes more sense now that I reread it.  I was thinking man, 100Mb on a 1Gb connection is good?     
No problem.  Good catch.    My original post to the LeCroy forum:

A short video showing the results of adding a 1000Gb board to the Wavemaster.  I used an Intel PRO/1000 GT Ethernet board which supports off loading some of the processing that the OS would normally have to do. 

I can leave both ports attached to the switch, each with their own IP and select the card I want to use from Labview.   XStream has no problems with it.   

I ran some tests with larger MTU size, Nagle enabled, changing the DSOs software priority and direct connection to the PC rather than using the Cisco switch.   Gains were minimal.

The one thing that I do notice that is not in the video, at 20GS/s the poor DSO has no time left to service the Ethernet.   Depending on what you are doing, I have seen average data rates as poor as 10Mb-20Mb with the 100Mb port.    In all cases the add-on board yielded better performance.   

If you don't use LACP to aggregate the ports on the NiC, then running each on it's own IP actually increases processing overhead.  You basically have an idle port, trying to look for data.  If you want to divide packets across the aggregate then LACP needs to be in place throughout the chain...both source and destination, and ANY device (switch etc) in-between needs to have those links operating as a "team".  If you team those ports, you don't exactly have a 2Gb/s port either, as there is overhead in the LACP. 

Intel PRO NiC is top tier kit....a lot of older Cisco switches don't support (802.3ad) dynamic links.....also running into a switch is not a point to point connection.....the switch re-prioritizes packets, depending on lots of things.....you can, however tag packets with priority...using QOS. 

I know that is all a bit off topic here, but just adding a bit of insight on how that all comes together in the real world.  I had a brief stint as a Cisco tech (CCNA cert) and thought some of that jargon might shed some light on some faults in methodology. 

Larger MTU doesn't necessarily benefit things.....a lot of devices don't handle jumbo frames in the same way.  Generally MTU of 9000 or more doesn't necessarily yield the result you might expect.....for example intel PRO NiC might call a jumbo frame 9000 MTU and a Cisco switch might call it 9090...etc etc etc....it's an endless clusterfuck of manufacturers not being on the same page....and a very loose classification about what a "jumbo frame" really is.....as a general rule stay away from jumbo frames....they very often don't help anything, and very often hurt things.....unless you have really sussed out the need, and entire chine of events that are handling that packet (and assuming that the source is even packaging that at the MTU).

[joeqsmith]

If you want to divide packets across the aggregate then LACP needs to be in place throughout the chain...both source and destination, and ANY device (switch etc) in-between needs to have those links operating as a "team".  If you team those ports, you don't exactly have a 2Gb/s port either, as there is overhead in the LACP. 

I can leave both ports attached to the switch, each with their own IP and select the card I want to use from Labview.   

I saw no difference in performance leaving them connected to the switch.   No attempt was made to team the ports.   The one on the DSO is again a 100Mb.  So yea, 2Gb/s with them combined is not going to happen.  Forget the overhead.

also running into a switch is not a point to point connection.....the switch re-prioritizes packets, depending on lots of things.....you can, however tag packets with priority...using QOS. 

I never stated that running through a switch was point to point.  Read it again eagle eyes.   

I ran some tests with larger MTU size, Nagle enabled, changing the DSOs software priority and direct connection to the PC rather than using the Cisco switch.   Gains were minimal.

Just tried a few quick tests, left it with the defaults and called it a day.   No big deal or effort. 

[TunerSandwich]

I never stated that running through a switch was point to point.  Read it again eagle eyes.   

Eagle eyes?  no need to be rude you know, this isn't a pissing contest.....I was trying to help you understand your flawed methodology.  If you want to play it like that though....best of luck, just don't be surprised with the responses you are getting.....if you are getting MB and Mb confused, and then telling people they are wrong, you aren't going to have much luck....

sheesh was just trying to help you.....I guess no good deed goes unpunished.   

Either way, still love ya buddy and best of luck <3

[joeqsmith]

I know that is all a bit off topic here, but just adding a bit of insight on how that all comes together in the real world.  I had a brief stint as a Cisco tech (CCNA cert) and thought some of that jargon might shed some light on some faults in methodology. 

Off topic??  Really?         This thread is a free for all.   

Really, if someone were to go out and buy a brand new DSO to look at their square waves, I think this is all good info to consider!  Press on....

[joeqsmith]

I never stated that running through a switch was point to point.  Read it again eagle eyes.   

Eagle eyes?  no need to be rude you know, this isn't a pissing contest.....I was trying to help you understand your flawed methodology.  If you want to play it like that though....best of luck, just don't be surprised with the responses you are getting.....if you are getting MB and Mb confused, and then telling people they are wrong, you aren't going to have much luck....

sheesh was just trying to help you.....I guess no good deed goes unpunished.   

Either way, still love ya buddy and best of luck <3

Pissing contest??       I was not trying to be rude.  Just pointing out that you too make mistakes when you are reading.  We all do.  Rolls off me no problem.  I screw up all the time.   

[Wuerstchenhund]

TunerSandwich beat me to it so I don't think it's necessary to reiterate where your misunderstanding is. Just let me address this:

Agilent taking on a LeCroy...
 
Article that explains dead times and compares a few scopes...
http://cp.literature.agilent.com/litweb/pdf/5989-7885EN.pdf

Agilent marketing material as source? Seriously? From a company that has a widely known history of twisting reality up to borderline lying?

I haven't looked at the video but the pdf file is typical Agilent. Based on the listed waveform rates it seems the unspecified WaveSurfer is a WaveSurfer 400 (the first compact LeCroy Windows lower mid-range scope, which ran XP but overall was a very basic scope), which has been out of production for roughly a decade. The WaveRunner waveform data very much looks like a WaveRunner2 LT, which is a VxWorks based scope introduced in 2001 which was stopped being sold roughly 11 years ago. And the WaveJet looks like a WaveJet 300 (non-A) which is a similarly old model. This Agilent paper is dated 2014, but it seems for them to get their point across LeCroy had to compare their current scopes with 10+ year old competitor models. Not that this is surprising, considering their history of being sparse with the full truth.

They also seem to ignore is that most LeCroy scopes reach their max waveform rates in segmented mode. Your WM8k, if I remember right (I don't have the data at hand for that model), is spec'd with around 100k wfms/s. My WP7300A is spec'd with up to 150k wfms (which it does achieve), and TunerSandwich's and my WR64Xi is spec'd with 1.25M wfms/s (which it does achieve as well). Scopes starting with the WRXi also have a mode called "WaveStream" which lets the scope run at much higher update rates than in normal mode. So even though these scopes are pretty old by today's standards they still can achieve high waveform rates, if operated correctly. Of course none of that is mentioned by Agilent.

I guess this is why Agilent obviously had to resort to older models for their "comparison" to "take on LeCroy", because LeCroy's current scopes had look their scopes like toys (at least in the mid-range and high-end, LeCroy's entry level line is still crap). So I guess the bottom line is that their 2014 scopes do pretty well against 10+ year old scopes from their competitors.

Well done Agilent 

[TunerSandwich]

TunerSandwich beat me to it so I don't think it's necessary to reiterate where your misunderstanding is. Just let me address this:

Agilent taking on a LeCroy...
 
Article that explains dead times and compares a few scopes...
http://cp.literature.agilent.com/litweb/pdf/5989-7885EN.pdf

Agilent marketing material as source? Seriously? From a company that has a widely known history of twisting reality up to borderline lying?

I haven't looked at the video but the pdf file is typical Agilent. Based on the listed waveform rates it seems the unspecified WaveSurfer is a WaveSurfer 400 (the first compact LeCroy Windows lower mid-range scope, which ran XP but overall was a very basic scope), which has been out of production for roughly a decade. The WaveRunner waveform data very much looks like a WaveRunner2 LT, which is a VxWorks based scope introduced in 2001 which was stopped being sold roughly 11 years ago. And the WaveJet looks like a WaveJet 300 (non-A) which is a similarly old model. This Agilent paper is dated 2014, but it seems for them to get their point across LeCroy had to compare their current scopes with 10+ year old competitor models. Not that this is surprising, considering their history of being sparse with the full truth.

They also seem to ignore is that most LeCroy scopes reach their max waveform rates in segmented mode. Your WM8k, if I remember right (I don't have the data at hand for that model), is spec'd with around 100k wfms/s. My WP7300A is spec'd with up to 150k wfms (which it does achieve), and TunerSandwich's and my WR64Xi is spec'd with 1.25M wfms/s (which it does achieve as well). Scopes starting with the WRXi also have a mode called "WaveStream" which lets the scope run at much higher update rates than in normal mode. So even though these scopes are pretty old by today's standards they still can achieve high waveform rates, if operated correctly. Of course none of that is mentioned by Agilent.

I guess this is why Agilent obviously had to resort to older models for their "comparison" to "take on LeCroy", because LeCroy's current scopes had look their scopes like toys (at least in the mid-range and high-end, LeCroy's entry level line is still crap). So I guess the bottom line is that their 2014 scopes do pretty well against 10+ year old scopes from their competitors.

Well done Agilent 

I also found myself laughing at the Agilent sample rates being touted as "industry leading" "groundbreaking" "unheard of price to performance" etc etc etc etc.....and by that token, found myself rolling on the ground howling when Tek markets the MDO by the same merits.....

It seems like even juan huong lo can offer specs like those.....for pennies on the "big guys" dollars.....and forget it when even comparing to something LeCroy moved on from over 10 years ago....

One thing I will give Agilent over LeCroy though....they don't dick around when it comes to processing performance.....they make easily the most responsive scopes I have ever put my hands on....LeCroy might have gotten better at this, as the computing power in their devices has gone up, but it's still offloaded to a general purpose microprocessor and OS.....and obviously Tek is off in some bubble of another universe when they think their products are competitive (in that regard)

Agilent seems to have a nice way of packaging their equipment into very very nice Ui's....fast to respond, truly excellent layouts....logical hierarchies etc etc....but then when it comes down to the "real" specs....it the same old repackaged chips, from 2 generations ago....which admitedly LeCroy is doing as well....however their chips from "2 generations ago" still seem to offer "more"....

It's very difficult to wade through the bullshit in new scopes and other t&m gear.....makes you just want to buy something that is already "obsolete" but still does exactly what you NEED, and have a good chuckle over the marketing BS some of these companies use to keep the consumer engine running.....

[TunerSandwich]

I haven't looked at the video

I just watched it, and that is the most feeble basis for comparison I have ever seen....he basically says that "although you can do the same things on the lecroy, you have to know what you are doing.....on the agilent you just draw a box" (this is regarding triggering).....so the marketing here is buy Agilent, because you don't need to know anything about how things work to use it....are you serious?  If you can't set-up a basic trigger function, then you have no idea about what you are measuring, how it works, how to solve a potential problem (even if your scope can find it) etc etc etc....

If I may be so bold to revise this marketing video....and sum it up in one catchy phrase, which will most certainly sell it....."Agilent : scopes for those with no time to think

To be fair I have seen some of this same bullshit comparison marketing from LeCroy as well....albeit slightly less ridiculous....why can't these companies just show what they sell, what it does, how much it costs, and what the terms are....I already know what i need, without them telling me who else is doing what.....and then assuming I believe one word of it.  Save the money, discount the scope, give me a compelling incentive on that basis (value) and move on.... I already like your products Agilent and don't need a fluffer

[Wuerstchenhund]

I also found myself laughing at the Agilent sample rates being touted as "industry leading" "groundbreaking" "unheard of price to performance" etc etc etc etc.....and by that token, found myself rolling on the ground howling when Tek markets the MDO by the same merits.....

Indeed. I guess the only "industry leading" thing from them is the amount of BS in their marketing stuff.

One thing I will give Agilent over LeCroy though....they don't dick around when it comes to processing performance.....they make easily the most responsive scopes I have ever put my hands on....LeCroy might have gotten better at this, as the computing power in their devices has gone up, but it's still offloaded to a general purpose microprocessor and OS.....and obviously Tek is off in some bubble of another universe when they think their products are competitive (in that regard)

Agilent seems to have a nice way of packaging their equipment into very very nice Ui's....fast to respond, truly excellent layouts....logical hierarchies etc etc....but then when it comes down to the "real" specs....it the same old repackaged chips, from 2 generations ago....which admitedly LeCroy is doing as well....however their chips from "2 generations ago" still seem to offer "more"....

I have to disagree here a little bit. It's true that Agilents scopes are very responsive, but the same is true for newer LeCroy scopes as well. A DSOX2k/3k is a very responsive scope (don't forget that these are relatively simple scopes using some closed down version of Windows CE), but the same is true for the WaveSurfer 3000 (LeCroy's equivalent of the DSOX3k(T) which is also a closed down Windows Embedded based scope) which is similarly responsive. Newer LeCroy's scopes (X-Stream II using PCIe) that run a full version of Windows are as much responsive as their Agilent/Keysight counterparts.

No argument about Tek who seems to be stuck in the past.

Older LeCroy Windows scopes (X-Stream I scopes which are based on 32bit PCI) like your WRXi could often feel a bit laggy as they were pretty much underpowered, simply because LeCroy cut some corners on CPUs (slow Celerons with small caches, resulting in the CPU getting maxed out regularly) and RAM (which is a bit ridiculous, considering the low prices of better CPUs and the high price tags of these scopes). But these problems can be overcome by simple upgrades. On my WR64Xi, general responsiveness improved noticably after I upgraded from the slow Celeron 1.3Ghz/512k to a Pentium-M 1.8GHz/2MB, the RAM to 1GB (max for that scope) and the painfully slow 4200rpm IDE drive to a modern SATA 5400rpm hard drive (installing updated drivers for chipset, gfx etc helped, too). On my WavePro 7300A (which already came with the LeCroy upgraded processor, a P4 2.53GHz with 512k cache and 533MHz FSB, as well as 2GB RAM), changing the processor to a P4 3.2GHz (1MB cache, 800MHz FSB), upgrading the RAM to 3GB and replacing the old IDE hard drive with a fast intel SATA SSD320, the scope went from laggy to instantaneous reaction to inputs. It's now easily as responsive as the Agilent DSO9k and 90k scopes I use at work.

As to Agilent's UI, I agree for their entry level scopes (i.e. DSOX2k/3k) which do have a nice UI, but as to their desktop Windows based scopes I think the UI isn't great. Yes, they have touch, but it still is pretty obvious that the whole thing was originally designed with mouse control in mind, not with touch, and that it's all based on the mouse UI of the old Infiniium 54800 Series running Windows95 (which wasn't exactly a stellar example of great UI design). Recent scopes gave the UI a bit of an overhaul, but the main flaws remain.

Agilent scopes do have a pretty simple front panel layout, though, and usually come with individual vertical controls for each channel. Aside from the WR6k(A), WP7k(A) and WM8k(A) LeCroy still has a single vertical control for all channels, and while the general layout of most LeCroy scopes is pretty similar across all products (aside WaveAce/WaveJet and WS3k), things like the SUperKnob on the WR6zi/HDO can be confusing to users unfamiliar with that scope.

How important individual vertical controls are is certainly a thing of individual preference. I enjoy the individual knobs on my WP7kA, but the single control on other LeCroy scopes never bothered me (but then I also liked the single knob front panel of the early HP 54500 Series).

It's very difficult to wade through the bullshit in new scopes and other t&m gear.....makes you just want to buy something that is already "obsolete" but still does exactly what you NEED, and have a good chuckle over the marketing BS some of these companies use to keep the consumer engine running.....

Agreed. Not that this is a bad option, though, as buying older gear (especially if it's still supported) can actually save you a lot of money, and in some cases (i.e. Rigol and Siglent scopes) leave the beta testing to someone else.

[EV]

Could this measurement be run without the RG58 coax, connectors and related adapters? Use only a single adapter if possible between the S4 head and generator output as there appears to be a reflection from the RG58 coax/connectors/adapters.

See circled areas in this altered image:



Bernice

Yes it is possible to connect Tek 284 directly to S-4 sampling head with 20 dB attenuator but not easy. It is difficult without a big table and I don't have it now.  These reflections do not bother me. There are same reflections in pictures 1 and 2 which are taken without attenuator between the RG58 cable and scope. Look at my reply #249.

[Wuerstchenhund]

I just watched it, and that is the most feeble basis for comparison I have ever seen....he basically says that "although you can do the same things on the lecroy, you have to know what you are doing.....on the agilent you just draw a box" (this is regarding triggering).....so the marketing here is buy Agilent, because you don't need to know anything about how things work to use it....are you serious?  If you can't set-up a basic trigger function, then you have no idea about what you are measuring, how it works, how to solve a potential problem (even if your scope can find it) etc etc etc....

If I may be so bold to revise this marketing video....and sum it up in one catchy phrase, which will most certainly sell it....."Agilent : scopes for those with no time to think

I only had a quick glance at the video, and I agree, it's ridiculous. The first thing that comes to mind is why Agilent felt the need to compare their 2013 scope with a LeCroy scope that came out 8 years earlier and that in the meantime has been succeeded by two generations (WRXi-A, WR6zi).

The firmware on the LeCroy must have been pretty old as well. Notice how it says "LeCroy" in the corner, not "Teledyne LeCroy"?

I guess Agilent was well aware that they needed an 8yr old model to compare to as the WR6zi would have made their DSOX4k like a toy. Which it is compared to a WaveRunner, really, as the correct equivalent would be the WaveSurfer Series.

The other thing I noticed is the instable trigger on the LeCroy, which doesn't look right to me. I guess this guy in the video either has no clue or he deliberately tried to make a competitor look bad.

But overall I'm not surprised, that is exactly the type of crap that Agilent has pulled like forever.

To be fair I have seen some of this same bullshit comparison marketing from LeCroy as well....albeit slightly less ridiculous....

I can't say that I have seen anything even closely similar from LeCroy. In fact, I can't remember ever having seen a video where they "compare" their scope against a competitor's, they always only show their own scopes. Of course they make everything look easy and highlight their selling points (well, who doesn't, that's marketing). But that's about it.

The only place where I saw LeCroy talking about competitors' scopes were a few whitepapers like this:
http://cdn.teledynelecroy.com/files/whitepapers/wp_interpolation_102203.pdf
But even there I'd say it's far from the level of BS you'll find in almost any Agilent whitepaper. All the tests are well described, as are the results, and should be easily reproducable. Looks pretty reasonable to me.

I think there's a huge difference between selling your stuff by putting a positive spin on it and twisting reality up to borderline lying.

why can't these companies just show what they sell, what it does, how much it costs, and what the terms are....I already know what i need, without them telling me who else is doing what.....and then assuming I believe one word of it.  Save the money, discount the scope, give me a compelling incentive on that basis (value) and move on.... I already like your products Agilent and don't need a fluffer

I wonder the same. My pet peeves are "Request Quote" buttons. What is hell the problem with just listing how much the damn thing costs? Agilent has prices on the US site but on most variants for other countries (including the UK) all you get is "Request Quote". It's different if I want to order or negotiate but more often than not I find myself thinking that if I have to go through a sales droid to get a simple price that I rather not bother at all.

LeCroy's website is even worse. It lists the base price for some scopes but for everything else I have to through a quote request. Seriously? Why can I configure a luxury car online which comes with hundreds of options, but can't do the same for a scope?

And then there's Tek who's sales droids are even calling me when I dared to download some spec sheet or manual from their website. I guess they must be really desperate these days.

[Rupunzell]

That is not the way test gear was once sold. The hewlett packard or Tektronix sales folks would visit to chat about their latest offerings, bring in the demo as requested then answer ALL related questions to what is and what is not. And.. they did specials if that was a better T & M solution.

*Zero pressure sales..

*Vintage hewlett packard & Tektronix printed catalogs had the price of said instrument and accessories in print.

If there were problems, they were quickly resolved within the designed in limits of said test gear. Post sales support was often good to excellent and most of all had few if any "bugs" that were baked in requiring "updates" to exterminate said bugs. Test gear was expected to do their intended job, function as required with zero grief, day after day, year after year. Yes, they got their periodic calibration and maintenance to help them stay healthy as test gear was considered an investment back then.

That has all changed today to Buy It Now, then toss it out soon as it's out of warranty (Bean counters & investors kinda demand this today). Yes, technology and measurement needs move forward, but keeping perspective on what is actually needed to get that measurement and testing done -vs- the latest and greatest with every fantasy bell & whistle turned into reality in that new box is not always a good thing. Really a matter of knowing precisely what is needed -vs- what is nice to have under the light of an orange moon.



Bernice

I wonder the same. My pet peeves are "Request Quote" buttons. What is hell the problem with just listing how much the damn thing costs? Agilent has prices on the US site but on most variants for other countries (including the UK) all you get is "Request Quote". It's different if I want to order or negotiate but more often than not I find myself thinking that if I have to go through a sales droid to get a simple price that I rather not bother at all.

LeCroy's website is even worse. It lists the base price for some scopes but for everything else I have to through a quote request. Seriously? Why can I configure a luxury car online which comes with hundreds of options, but can't do the same for a scope?

And then there's Tek who's sales droids are even calling me when I dared to download some spec sheet or manual from their website. I guess they must be really desperate these days.

[joeqsmith]

That is not the way test gear was once sold.

Some of them still come on-site and leave the equipment with us.   I don't like Keysight tossing their sales like they did.  We had Copper Mountain in a while back.  Great presentation, spent the day going over their product.     

Looking at this particular DSO's dead time:

10GS/s, collecting 5Ms requires 640ms.   If the PCI bus could handle 60MB sustained, it would require 83ms to move the data or about 13% of the bus BW.   Say the Ethernet can move the data at 50Mb/s which is about what I was getting with the built in board.   So about 6.25MB/second.   Moving 5Ms will require about 800ms.     

If we want to handle the data and not miss any of the little data the DSO does happen to collect, the 100Mb won't cut it.     At 400Mb/s with the 1G Ethernet, this time drops to 100mS.  Maybe enough time to move the data to the modern PC, post process and display it.   

At 10GS/s and collecting 200Ks requires 35ms.   Staying with 60MB on the PCI bus, it would require 3.33ms or about 9.5% of the bus.  The Ethernet transfer would be about 32ms using 100Gb.

For 20GS/second collecting 32MS (max for this DSO) requires 9.486 seconds.    So that is 1.6 ms of data collected out of the 9.486 seconds of total data.    Using the same 60MB PCI BW, that's about 533.33ms to move this data.    Or about 5.6% of the PCI bus being used.   

So say 534.93 ms is used to collect the data and move it through the PCI bus to the PC.   There's 8.951 seconds to get the data onto the screen.   Keep in mind, there's no math enabled and only one channel is being used.

My old LeCroy Wavemaster 8500A has an Intel P4 2.533GHz with 512KB L2 cache and 2G of RAM installed.  It also has a SSD.

Today I pulled out an old Agilent Infiniium MSO8104A.  This DSO is a little newer but much lower end than the Wavemaster, maybe a 1/4 of the price.    It also uses XP-Pro.  It has an Intel Celeron D 3.20GHz  with 256K L2 cache.    Is has the original mechanical drive in it.     It does however come with a 1Gb Ethernet port.   

Both DSOs have the same FSB speed. 

I repeated the test on the Wavemaster collecting at 5GS/s, 5M samples.  This requires 531 ms.   
Using the Infiniium collecting at 4GS/s, 8.2M samples required 42 ms.    I was actually running some math on the Infiniium and still out performing the LeCroy.   

I tried to run an FFT with the Infiniium and see what it would display at the sample frequency.  They don't seem to allow you to do this.

[Wuerstchenhund]

My old LeCroy Wavemaster 8500A has an Intel P4 2.533GHz with 512KB L2 cache and 2G of RAM installed.  It also has a SSD.

If it's an 'A' then it also has an intel D865GCL mainboard with AGP.

Today I pulled out an old Agilent Infiniium MSO8104A.  This DSO is a little newer but much lower end than the Wavemaster, maybe a 1/4 of the price.    It also uses XP-Pro.  It has an Intel Celeron D 3.20GHz  with 256K L2 cache.    Is has the original mechanical drive in it.     It does however come with a 1Gb Ethernet port.   

What it also comes with is an Adlink M880 or intel D915GUX PCI Express mainboard (depending on the version of your scope) which both are PCI Express boards.

I repeated the test on the Wavemaster collecting at 5GS/s, 5M samples.  This requires 531 ms.   
Using the Infiniium collecting at 4GS/s, 8.2M samples required 42 ms.    I was actually running some math on the Infiniium and still out performing the LeCroy.

Not surprising when considering that the Agilent has a Gbit NIC which is connected via its's own PCI Express lane so doesn't affect the PCI bus that is used for the Acquisition system.

On the LeCroy the 100Mbps NIC also doesn't use the PCI bus, it's connected via CSA to the chipset.

It shouldn't really come as a surprise that just plugging in a PCI Gbit NIC won't give you the same performance.

The bottom line of all this is that if pulling sampling data out via network is of upmost importance for you then the WM8kA is simply the wrong scope, and plugging in some network card certainly won't change that. LeCroy's strenght lies in its internal processing capabilities, and that's why people buy them, not to be used as simple acquisition system for external processing. And really, if all you need is a sampling system that delivers the data to your PC as fast as possible then bench scopes are generally not a good choice, and you really should have a look at something like a PXI system which is much better for what you're trying to do.

I tried to run an FFT with the Infiniium and see what it would display at the sample frequency.  They don't seem to allow you to do this.

There's a lot of stuff you can't do on the Agilent that you can do on the LeCroy.

[Wuerstchenhund]

More Rigol DG1062z Square Wave Tests

Since the previous screenshots gave me eyesore (green on white, yuck!) I thought let's just re-do them. This time around however I not only tested at 1MHz and 25MHz but also at 5MHz, 10MHz, 15MHz and 20MHz.

As before the SA is an Agilent E7495B, the cable a Huber & Suhner Sucoflex 100 (up to 18GHz) and the BNC-to-N adapter a Huber & Suhner rated to 18GHz as well.

The various shots show how the square wave composition deteriorates with increasing frequency. The 1MHz one shows pretty much all the harmonics one expects, but at higher frequency this changes until at 25MHz it's essentially just a two tone signal.

[joeqsmith]

It shouldn't really come as a surprise that just plugging in a PCI Gbit NIC won't give you the same performance.

Just to be clear, when I was measuring the dead times of the two DSO's, Ethernet was not used.   I never looked at how fast I could pull data off the Agilent.   

The bottom line of all this is that if pulling sampling data out via network is of upmost importance for you then the WM8kA is simply the wrong scope, and plugging in some network card certainly won't change that. LeCroy's strenght lies in its internal processing capabilities, and that's why people buy them, not to be used as simple acquisition system for external processing. And really, if all you need is a sampling system that delivers the data to your PC as fast as possible then bench scopes are generally not a good choice, and you really should have a look at something like a PXI system which is much better for what you're trying to do.

To be clear, the Wavemasters software and PC are out dated and slow.  What would you expect for a 13 year old PC based instrument.   Using a faster Ethernet card on the PCI bus will improve download performance.     

The high end LeCroys do have some very impressive features when it comes to processing the data.   Even my old 7200 with its 68000 VME chassis has far more features than most low end modern DSOs.   Using these dated high end DSOs for home hobbies has been a blast.   LeCroy does not seem to hold a lot of resale value and as they age, like the old Wavemaster, the prices drop.   

I'm sure there are many reasons why people buy what they buy.   Personally I like seeing some of the old equipment in use and certainly am not going to put people down for how or why they do what they do.    I just enjoy the fact that so many of us enjoy playing with electronics and are willing to share there experiences.   

[Wuerstchenhund]

It shouldn't really come as a surprise that just plugging in a PCI Gbit NIC won't give you the same performance.

Just to be clear, when I was measuring the dead times of the two DSO's, Ethernet was not used.   I never looked at how fast I could pull data off the Agilent.   

Then I guess I misunderstood your post, for which I apologize.

To be clear, the Wavemasters software and PC are out dated and slow.  What would you expect for a 13 year old PC based instrument.

It doesn't have to be. If it's an 'A' model then the CPU can be upgraded to a P4 with 800MHz FSB and 1MB cache, and especially the cache helps as this is where X-Stream does all its calculations.

The software doesn't have to be old as well. On your videos I noticed that it still says "LeCroy" in the lower left corner which suggests that you're running a very old firmware. The WM8kA is still supported, and the latest software update came out just a couple of months ago, and will upgrade your scope to the same version that runs on the latest LeCroy scopes (although it won't also give you all new features of course).

Using a faster Ethernet card on the PCI bus will improve download performance.

Probably, but again it might still lead to side effects. If you didn't see any then good for you, but my point was that this doesn't mean there are none or that any such upgrades will be trouble-free (which often won't be).

The high end LeCroys do have some very impressive features when it comes to processing the data.   Even my old 7200 with its 68000 VME chassis has far more features than most low end modern DSOs.   Using these dated high end DSOs for home hobbies has been a blast.   LeCroy does not seem to hold a lot of resale value and as they age, like the old Wavemaster, the prices drop.   

That's true, although very high bandwidth scopes with 50ohms only inputs like the WaveMaster are generally cheaper as most people want 1M inputs and BNC. But I guess the main reason for used LeCroy scopes often being so cheap is that when thinking 'scope' most people think 'Tek' and 'Agilent', and for home users maybe 'Rigol' and 'Siglent' as well, but that's about it. LeCroy seems to be mostly overlooked on the second hand market, which is good as like you say it keeps prices low. And they did and still make some of the most advanced scopes on the market.

[Rupunzell]

BNC connectors do not work well above 3 Ghz, they will be pressed to achieve a return loss of better than 20db (their mechanical dimensions and stability is a significant part of this problem). Only the very best BNC connectors work to 4-5 Ghz and they might achieve 26db return loss.

To believe any BNC connector is rated and will function to 18Ghz is pure folly.

Cheap BNC connectors will be pressed to operate even to 1 Ghz.

If manufactures of this Ghz stuff is honest about Ghz performance, BNC connectors will not be used at all.


Beyond this, there is the common 50 ohm BNC connector and less common 75 ohm BNC connector which is somewhat compatible with the 50 ohm variety, but some 75 ohm BNC connectors are NOT compatible with 50 ohm BNC connectors.


Bernice

As before the SA is an Agilent E7495B, the cable a Huber & Suhner Sucoflex 100 (up to 18GHz) and the BNC-to-N adapter a Huber & Suhner rated to 18GHz as well.

[Wuerstchenhund]

BNC connectors do not work well above 3 Ghz, they will be pressed to achieve a return loss of better than 20db (their mechanical dimensions and stability is a significant part of this problem). Only the very best BNC connectors work to 4-5 Ghz and they might achieve 26db return loss.

Some modern higher bandwidth scopes use connectors that look like BNC (and are mechanically compatible) but aren't and work pretty well up to 10GHz. For example, the new Keysight MSO-S has such connectors, and this scope is rated to 8GHz.

I have some adapters that use similar connectors, and some are rated to 18GHz, although the loss above say 10GHz gets pretty high.

To believe any BNC connector is rated and will function to 18Ghz is pure folly.

No-one said anything about BNC being suitable to 18GHz.

[Rupunzell]

For those who want a DSO, get a LeCroy.

If 1 meg is needed at the probe tip, use an active probe with the 50 ohm input and accept the limitations of 1 meg ohm with X pF at the probe tip. Ghz instrumentation are 50 ohm input are a must if one is to be honest about dealing with the realities of Ghz capability.


Bernice

That's true, although very high bandwidth scopes with 50ohms only inputs like the WaveMaster are generally cheaper as most people want 1M inputs and BNC. But I guess the main reason for used LeCroy scopes often being so cheap is that when thinking 'scope' most people think 'Tek' and 'Agilent', and for home users maybe 'Rigol' and 'Siglent' as well, but that's about it. LeCroy seems to be mostly overlooked on the second hand market, which is good as like you say it keeps prices low. And they did and still make some of the most advanced scopes on the market.

[Rupunzell]

Any BNC at 10 Ghz, not gonna work. Any manufacture that rates their BNC to 18 Ghz is being extremely dis-honest and deceptive.


Bernice

I have some adapters that use similar connectors, and some are rated to 18GHz, although the loss above say 10GHz gets pretty high.

No-one said anything about BNC being suitable to 18GHz.

As before the SA is an Agilent E7495B, the cable a Huber & Suhner Sucoflex 100 (up to 18GHz) and the BNC-to-N adapter a Huber & Suhner rated to 18GHz as well.

[Wuerstchenhund]

Any BNC at 10 Ghz, not gonna work. Any manufacture that rates their BNC to 18 Ghz is being extremely dis-honest and deceptive.

Yeah, well, it seems you don't get what 'rated' means. If a part is 'rated' up to 18GHz it merely means that it's properties up to 18GHz are known. It doesn't necessarily mean 'guaranteed to work great at' or 'zero loss at'.

You can rate a piece of string to 100GHz, no problem. It doesn't mean it's any good at that frequency, though.

As to what the manufacturer rating is worth, I certainly wouldn't trust a cheap part from a Chinese ebay seller but I an tell you from quite a bit of personal experience that the stuff you get from manufacturers like Huber & Suhner is pretty much spot-on. In fact, Huber & Suhner is one of the most renowed manufacturers for RF cables and stuff, and that's for a reason.

[tautech]

Any BNC at 10 Ghz, not gonna work. Any manufacture that rates their BNC to 18 Ghz is being extremely dis-honest and deceptive.

Yeah, well, it seems you don't get what 'rated' means. If a part is 'rated' up to 18GHz it merely means that it's properties up to 18GHz are known. It doesn't necessarily mean 'guaranteed to work great at' or 'zero loss at'.

You can rate a piece of string to 100GHz, no problem. It doesn't mean it's any good at that frequency, though.

As to what the manufacturer rating is worth, I certainly wouldn't trust a cheap part from a Chinese ebay seller but I an tell you from quite a bit of personal experience that the stuff you get from manufacturers like Huber & Suhner is pretty much spot-on. In fact, Huber & Suhner is one of the most renowed manufacturers for RF cables and stuff, and that's for a reason.

While you are both to'ing and fro'ing somebody should state a load impedence which WILL make a massive difference at those frequencies.

[Wuerstchenhund]

LeCroy is not a mainstream brand.   When I think LeCroy, I think physics.  Well, not so much anymore.   My 7200 even has some support in the software for TOF.  Crude yes but the fact it has anything gives an idea of their target market back then.   

Was the same with me. I knew they existed but never considered them until two years ago when I had the chance to get a WaveRunner LT224 for cheap. Now I regret not having looked at their scopes earlier.

They still offer a 1Meg input driver but price for a few new ones was more than the Wavemaster cost.   

I see them occasionally on ebay, and usually for pretty excessive price tags.

I think LeCroy solved that pretty well with the current WavePro 7zi  and WaveMaster 8zi by giving each channel two inputs (ProLink and ProBus with BNC). Another solution I haven't seen anywhere else.

It would make the old Wavemaster more useful as a general purpose scope.   I was playing around with a  few different op-amps to make a driver for the it.  These videos show a few of them. 

Interesting. It would certainly make the scope more useful for common application, and they wouldn't have to go very high bandwidth-wise (i.e. 500MHz). You could stick them in the case of an old ProBus probe (incomplete active probes often come up for little money).