Let’s Talk About LeCroy Scopes, AKA… the “Wuerstchenhund Holds Court” Thread

[nctnico]

Don't expect fast update rates. Everything is done in software on the Wavepro 7k series and the software isn't pushing the processor what it is capable off. Count on 1000 waveform updates/s tops in the best case scenario.

[PartialDischarge]

Someone with a Lecroy 12 bit scope (HDO*** ? ) can please tell me how the noise reduction with the enhanced resolution works on practice? ie does one need to setup another math channel with the enhanced res on it, or does it apply directly to the channel being mesasured like the High-res in Tek scopes?

[2N3055]

Someone with a Lecroy 12 bit scope (HDO*** ? ) can please tell me how the noise reduction with the enhanced resolution works on practice? ie does one need to setup another math channel with the enhanced res on it, or does it apply directly to the channel being mesasured like the High-res in Tek scopes?

Eres is a math function on these.
This is something Siglent SDS2000X HD does more versatile, because you can have ERES as acquisition mode and math channel...
Best...

Not enough homework... They have a Filter function in channels (that seems to to be ERes) and math ERes.
Thanks Martin!

[Martin72]

We got a HDO6034A at work, you can do enhanced resolution via math, but also directly in the channel menu.
Can make a pic from it tomorrow.

[PartialDischarge]

We got a HDO6034A at work, you can do enhanced resolution via math, but also directly in the channel menu.
Can make a pic from it tomorrow.

Yes please, take a pic of both ways and see if the noise reduction works and is the same.

[2N3055]

We got a HDO6034A at work, you can do enhanced resolution via math, but also directly in the channel menu.
Can make a pic from it tomorrow.

Yes please, take a pic of both ways and see if the noise reduction works and is the same.

Of course it works...
Question is: what are your expectations and criteria for it?

[PartialDischarge]

I just want to see how it is activated and that it works, even just for the usec division which is not much for these scopes, I don’t have access to one of these.  I have had already 2 customers who have these scopes but seem to have no idea on how to setup this mode or that it exists. There is serious lack of basic knowledge on how to measure with a scope in young engineers today, people measuring noise in pkpk instead of rms etc...

[2N3055]

I just want to see how it is activated and that it works, even just for the usec division which is not much for these scopes, I don’t have access to one of these.  I have had already 2 customers who have these scopes but seem to have no idea on how to setup this mode or that it exists. There is serious lack of basic knowledge on how to measure with a scope in young engineers today, people measuring noise in pkpk instead of rms etc...

I agree there is widespread lack of detailed knowledge.. In part because scopes have never been more powerful (complicated).
And also by nobody reading manuals anymore apparently..

ERes is quite well documented actually... See attachment.. There are several white papers on LeCroy site that go into even more details.

[nctnico]

I just want to see how it is activated and that it works, even just for the usec division which is not much for these scopes, I don’t have access to one of these.  I have had already 2 customers who have these scopes but seem to have no idea on how to setup this mode or that it exists. There is serious lack of basic knowledge on how to measure with a scope in young engineers today, people measuring noise in pkpk instead of rms etc...

If those scopes have some options, it is very likely that these include signal filtering. From my experience with Lecroy scopes these are even harder to setup but have the potential to create much steeper high pass, band pass and low pass filters which could be a better solution to isolate signals which live in a certain frequency band.

@2N3055:  I'd don't think the Eres principle is the problem but the user interface. From what I have seen from my Lecroy Wavepro 7k is that it is very powerfull but getting math & functions going, is far from trivial. You really need to know what you are doing and what you are after.

If the goal is to have a scope that can do high resolution and simple averaging functions, then other brands which simply have 'high res' and average modes are far easier to drive.

[Martin72]

Eres in the channelmenu..
Signal was stopped(because I had to give the DUT away... ), you can see some small disturbances on it.
With eres, the signal is clear.
But you can also use eres as a mathfunction ( 8....EIGHT mathchannels..LOL).

[2N3055]

I just want to see how it is activated and that it works, even just for the usec division which is not much for these scopes, I don’t have access to one of these.  I have had already 2 customers who have these scopes but seem to have no idea on how to setup this mode or that it exists. There is serious lack of basic knowledge on how to measure with a scope in young engineers today, people measuring noise in pkpk instead of rms etc...

If those scopes have some options, it is very likely that these include signal filtering. From my experience with Lecroy scopes these are even harder to setup but have the potential to create much steeper high pass, band pass and low pass filters which could be a better solution to isolate signals which live in a certain frequency band.

@2N3055:  I'd don't think the Eres principle is the problem but the user interface. From what I have seen from my Lecroy Wavepro 7k is that it is very powerfull but getting math & functions going, is far from trivial. You really need to know what you are doing and what you are after.

If the goal is to have a scope that can do high resolution and simple averaging functions, then other brands which simply have 'high res' and average modes are far easier to drive.

I agree ease of use is important.. But saying "as simple as possible but no simpler" comes to mind.
My problem with these "other scopes" is that they have something easy but no control or explanation what is happening to your signal..
So for real control you need to embrace complexity.. You can optimize UI but in the end you will still have more parameters to set than with a scope that simply does "something" to the signal with one click...
ERes should be quite simple: enable it and choose how many bits you want.. I attached excerpt from manual. And, quite frankly, people who cannot be bothered to read that much and understand it will have problems with basic electronics... Yes, I know, that sounds abrasive and insulting, but it is truth. 

If I had Wavepro 7000, I would buy a small Rigol, Siglent, Micsig etc.. in addition to it for noncritical daily type of work..
Not because Wavepro is too complicated, but it takes more time to setup. Like you say.  I agree with that. Saving time is important. But sometimes it takes hours to setup experiment. Scope setup time becomes miniscule part of that time.

[Someone]

With eres, the signal is clear.

The "same" +3 bits of enhancement produced different results and frequency cutoff ? Even when the timebase/samplerate seems to be the same?

[Martin72]

I didn´t change anything when swapped to the math functions.

[PartialDischarge]

C1 has a 20MHz low pass filter applied to it, but It seems the math function is taking the raw data from C1, which in part makes sense

[Performa01]

With eres, the signal is clear.

The "same" +3 bits of enhancement produced different results and frequency cutoff ? Even when the timebase/samplerate seems to be the same?

Martin used the 20 MHz bandwidth limiter for the input channel. So it's only consequent that the reported bandwidth in the channel menu cannot exceed 20 MHz.

By contrast, the math function does not care about the bandwidth limited source and reports the full ERES bandwidth.

[2N3055]

One thing I can see is that ESR (enhanced sample rate) is on.

One thing to note is that cutoff frequencies are consistent with 2.5 GS/s and 10 GS/s respectively (1.25 and 5GHz theoretical BW before ERES).
Which might mean that ERes in a channel is made from data before ESR, and in math after ESR (naturally).

I would disable ESR and try if then it is the same.

20 MHz BW limit should be physical, analog filter in channel input.
BW shown are for ERes alone, based on (Nyquist x 0,016) for 3 bit ... Or at least it should be like that.. 
Maybe scope "saw" use of BW20 limiter and "decided" to use 4x decimated data to save on filter taps..
But I doubt.
I would try disabling ESR first and try again.

[Martin72]

ERes is quite well documented actually... See attachment..

Seems the HDO6000A do have some more feature in it´s software- although it´s basically the same ( before buying the 6000 we got a 4000 on loan).
Because in the manual of the HDO6000/Waverunner 9000 there is the same part about Eres function like you attached in your post.
And one additional more, the possibility to choose Eres in the channelbox, see my pic below (It´s just this one sentence).
By the way, turning the channel to full bandwith changes nothing on the bandwith when Eres is +3bit on the channelmenu.

[HighVoltage]

I have always looked at LeCroy scopes as a niche market filler.

Over the years I only owed two LeCroy scopes and both were extremely bad in responding, when any kind of math or extra functionality was turned on.

I never had these problems with any of the Agilent / Keysight scopes.

[nctnico]

I tend to agree with that assessment. Although: are the Agilent / Keysight scopes you are referring to using decimated data or acquired data for math? One of the (few) good things about Lecroy scopes is that they use acquired data for math (not sure about the various rebadges they sell) .

[2N3055]

That is a sleazy comercial, not something I would expect from a great company..
(i don't like comparisons from LeCroy or Tek either, they all go too far in this kind of material)

Comparing 1 GHz/2.5 GS/s with a 8 GHz 40GS/s and noting the lather one is more accurate near 1 GHz...
And showing ENOB for only one amplitude that incidentally sits in Keysight  sweet spot...

As for Keysight scopes being more "responsive" to user input that is what they optimize for. There are people that do lots of simple, fast operations with a scope and demand "instantaneous" response to user commands.
Even if that means that scope is slow calculating.  I see that with my MSOX3104T compared to SDS6104H12.
Simple waveform view, edge trigger and it feels like analog scope.. up to 1 Meg trigs per sec.... Amazing.
I switch on math, and FFT updates every 2 seconds, and that is on puny 64 Kpoints.
At the same time SDS6104H12 will update 8 MEGpoint FFT several times a second...

I see your statement more as a testament you are doing specific type of work and use scopes in a way that Keysight concept suits you. And I have a feeling you mostly prefer Infiniivision series (3000/4000/6000).
Because S series in that video has same concept as LeCroys (just cruder), and is even slower to drive for everyday work.

LeCroy is niche, or not. They are great for R&D, science folks, test... They are "scopes with analysis lab built in". If you need that, they are first choice, if you don't, than you don't...
I find them logical to setup, but I never was a button twiddler, more of a make plan first before doing something...
We are all different and have different needs..

[HighVoltage]

Yes, you are correct, my comparison is with the Keysight Infiniivision Series 3000X,  4000X, and 6000X, which I use every day in my work. And for some reasons they are just perfect for my applications.

I don't have a S-Series nor have I used a Keysight S-Series scope. (Maybe one day!) The video compares two scopes in the same price range and the LeCroy does show some basic limitations. I also think they set the S-Series to 1 GHz bandwidth. One could probably also find limitations in Keysight scopes, no question!

My personal experience with LeCroy scopes have just been terrible. And yes, I know that LeCroy makes some amazing high end scopes for research but they are in a range of not affordable to normal businesses.

[nctnico]

That is a sleazy comercial, not something I would expect from a great company..
(i don't like comparisons from LeCroy or Tek either, they all go too far in this kind of material)

Comparing 1 GHz/2.5 GS/s with a 8 GHz 40GS/s and noting the lather one is more accurate near 1 GHz...

Actually, the effect shown in the video is sin x/x reconstruction going wrong on the Lecroy for some reason. With 2.5Gs/s there shouldn't be any problem showing a 1GHz sine wave. I'm not going point fingers as to where the problem is due to the nature of the video.

[2N3055]

Yes, you are correct, my comparison is with the Keysight Infiniivision Series 3000X,  4000X, and 6000X, which I use every day in my work. And for some reasons they are just perfect for my applications.

I don't have a S-Series nor have I used a Keysight S-Series scope. (Maybe one day!) The video compares two scopes in the same price range and the LeCroy does show some basic limitations. I also think they set the S-Series to 1 GHz bandwidth. One could probably also find limitations in Keysight scopes, no question!

My personal experience with LeCroy scopes have just been terrible. And yes, I know that LeCroy makes some amazing high end scopes for research but they are in a range of not affordable to normal businesses.

If you have found an instrument that is perfect for your use that is great!

As I said, I do own MSOX3104T and use it. Among my scopes, that is the one that replaces "old school" CRT scopes... It has many good sides, and many limitations, depending of what you ...

I know they limited input filter to 1GHz, but if you look at the FFT, it is brickwall response, sampled at 40 GS/s and with full 8 GHz bandwidth and then software discards anything above 1 GHz.. Keysight can even use ERES here, because of massive oversampling, which would explain very optimistic ENOB figures...

But , biggest point here is that they took two completely differently targeted instruments and compare them at uneven metrics.. That particular LeCroy is, for instance, used a lot in power electronics industry because of 12 Bit and comprehensive analysis packages available... Super high bandwidth would even be undesirable here...

[David Hess]

LeCroy is niche, or not. They are great for R&D, science folks, test... They are "scopes with analysis lab built in". If you need that, they are first choice, if you don't, than you don't...
I find them logical to setup, but I never was a button twiddler, more of a make plan first before doing something...
We are all different and have different needs..

My personal experience with LeCroy scopes have just been terrible. And yes, I know that LeCroy makes some amazing high end scopes for research but they are in a range of not affordable to normal businesses.

My understanding is that LeCroy oscilloscopes were originally descendant from high speed digitizers intended for the scientific research and nuclear weapon testing.  These applications require high speed, long record length, and unattended operation.  I think this is reflected in LeCroy preferring long record lengths while relying on post processing rather than real time processing during aquision.

I have noticed that modern oscilloscopes intended for use as automated test equipment also usually lack a responsive and easy to use front panel interface, as opposed to oscilloscopes intended for service work where the operator does not necessarily know what they are looking for, so a good interface is more important.

[Martin72]

By the way, turning the channel to full bandwith changes nothing on the bandwith when Eres is +3bit on the channelmenu.

Asked lecroy support for this.
He wasn´t sure but he think it´s because of the avaible 20Mhz BW limit why eres in the channel menu is also limited to 20Mhz.
Then a nice explaination followed about the eres filter function, I think I post it here tomorrow, maybe it´s interesting.