Author Topic: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?  (Read 4009 times)

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Online Sighound36

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #25 on: October 01, 2019, 10:00:27 pm »
Quote
I paid $400 (ex shipping) for one with some issues. But the good ones with some warranty seem to be in the $3k range. However if you have a bit more budget I'd go for a newer scope which likely doesn't like to immitate a vacuum cleaner.
The jitter specs for the trigger on the Wavepro 7200A is 1ps rms with an interpolator jitter of 2.5ps typical.

Respectable figures indeed I do have a respectable budget I could manage a basic 1Ghz Tek mso54  new but feel they could better options out there used and not looking like a Hoover would be beneficial
 Interestingly the rigol 8000 had the same 200ps as the lecroy 7200 specs st 225ps using the 0.35 method what really dictates the final s/n jitter figures?
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Online nctnico

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #26 on: October 01, 2019, 10:16:13 pm »
Quote
I paid $400 (ex shipping) for one with some issues. But the good ones with some warranty seem to be in the $3k range. However if you have a bit more budget I'd go for a newer scope which likely doesn't like to immitate a vacuum cleaner.
The jitter specs for the trigger on the Wavepro 7200A is 1ps rms with an interpolator jitter of 2.5ps typical.

Respectable figures indeed I do have a respectable budget I could manage a basic 1Ghz Tek mso54  new but feel they could better options out there used and not looking like a Hoover would be beneficial
 Interestingly the rigol 8000 had the same 200ps as the lecroy 7200 specs st 225ps using the 0.35 method what really dictates the final s/n jitter figures?
There should be a specification in the trigger section which tells the trigger jitter and interpolator resolution. Together these make up how much horizontal noise a digital oscilloscope has.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline 2N3055

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #27 on: October 01, 2019, 10:23:02 pm »
Quote
I paid $400 (ex shipping) for one with some issues. But the good ones with some warranty seem to be in the $3k range. However if you have a bit more budget I'd go for a newer scope which likely doesn't like to immitate a vacuum cleaner.
The jitter specs for the trigger on the Wavepro 7200A is 1ps rms with an interpolator jitter of 2.5ps typical.

Respectable figures indeed I do have a respectable budget I could manage a basic 1Ghz Tek mso54  new but feel they could better options out there used and not looking like a Hoover would be beneficial
 Interestingly the rigol 8000 had the same 200ps as the lecroy 7200 specs st 225ps using the 0.35 method what really dictates the final s/n jitter figures?

Rigol MSO8000  has minum timebase of 200ps. It's rise time is better than 175ps, very good.

Problem is, like Nctnico well noticed, is that there is no specification for trigger jitter. How can you measure jitter of your devices when you don't know what is jitter of the scope.
Worst thing is, it might even have decent spec on that, but Rigol didn't publish it. 

If my Picoscope 3406D can specify trigger jitter, at 3 ps RMS typical on a scope that sample at1 GS/s, than also Rigol can publish it.
They claim" 2ps resolution at 200 ps timebase" whatever that means, but no jitter spec.
But achieving 10ps or better jitter trigger is not trivial...
 

Online 0xdeadbeef

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #28 on: October 01, 2019, 11:06:21 pm »
To be fair, AFAIK R&S doesn't specify a trigger jitter for the RTM3000 or RTA4000 either. They do define a 1<ps jitter for the higher end RTE and RTO scopes though.
So obviously, the trigger jitter of an RTM3000 or RTA4000 is much worse than that or else they would most probably specify it.
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Online nctnico

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #29 on: October 01, 2019, 11:49:43 pm »
To be fair, AFAIK R&S doesn't specify a trigger jitter for the RTM3000 or RTA4000 either. They do define a 1<ps jitter for the higher end RTE and RTO scopes though.
So obviously, the trigger jitter of an RTM3000 or RTA4000 is much worse than that or else they would most probably specify it.
That is very likely. I don't think the RTM3000 and RTA4000 are aimed at doing jitter analysis at the picosecond level but more towards general purpose use.
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Online 0xdeadbeef

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #30 on: October 02, 2019, 12:02:31 am »
But they are in a price range where you would expect a trigger jitter specification. E.g. LeCroy doesn't specify a trigger jitter for the WS3000Z but they do specify it for the HDO4000 (≤3.5ps rms for >= 500MHz) or the Wavesurfer 510 (also (≤3.5ps rms) - where both are also general purpose scopes.

[Edit]
Surprisingly, the Siglent SDS5000X datasheet actually specifies a trigger jitter, namely "<100ps". While maybe a bit underwhelming, at least this is an honest specification.
« Last Edit: October 02, 2019, 12:23:43 am by 0xdeadbeef »
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Online tautech

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #31 on: October 02, 2019, 12:44:22 am »
But they are in a price range where you would expect a trigger jitter specification. E.g. LeCroy doesn't specify a trigger jitter for the WS3000Z but they do specify it for the HDO4000 (≤3.5ps rms for >= 500MHz) or the Wavesurfer 510 (also (≤3.5ps rms) - where both are also general purpose scopes.

[Edit]
Surprisingly, the Siglent SDS5000X datasheet actually specifies a trigger jitter, namely "<100ps". While maybe a bit underwhelming, at least this is an honest specification.
Yep just looked that up too and was thinking about a way to measure it using Measurement Stats.

Tie a wavegen clock to the scopes clock and set Period Stats in motion.
Better suggestions ?
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Online nctnico

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #32 on: October 02, 2019, 12:52:43 am »
It is much easier. Just apply a fast edge. It usually helps to crank the v/div down to get a steeper edge into the trigger circuit but the signal may be outside the visible range. If you are only interested in the edges then this will provide the best trigger accuracy.

Connecting an external clock doesn't do you any good because the trigger jitter is about the ability to reproduce the trigger position of a signal.
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Online tautech

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #33 on: October 02, 2019, 02:12:59 am »
Here you go.

100 KHz 5ns pulse with 2ns risetime, fastest I have from a SDG6022X. Siglent 1 GHz rated BNC cable.
NO clock syncing, just 2 standalone instruments.

Dots and Infinite persistence.
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Offline DrDiode

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #34 on: October 02, 2019, 05:22:23 am »
I purchased a RIGOL DS4000 Series Oscilloscope. I ordered the 200Mhz 4 Ch. version. at the time, there was a sale and a free bandwidth upgrade and every optional decode were included. The 3db point is 530Mhz and the scope triggers well up to 1Ghz, the hardware freq. counter works up to 1Ghz also. it has 4.0 GSa/s (interweave); 2.0 Gsa/s (non-interweave), Auto, 14k pts, 140k pts, 1.4M pts, 14M pts and 140M pts Memory Depth. it has the 50 Ohm mode to. I hope this helps.
 

Offline TurboTom

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #35 on: October 02, 2019, 07:01:49 am »
But they are in a price range where you would expect a trigger jitter specification. E.g. LeCroy doesn't specify a trigger jitter for the WS3000Z but they do specify it for the HDO4000 (≤3.5ps rms for >= 500MHz) or the Wavesurfer 510 (also (≤3.5ps rms) - where both are also general purpose scopes.


Some time ago, there has been a discussion on the jitter of the "Trigger Out" signal vs. the trigger event on some rigol scopes. Consensus was that these figures point to a pure software/digital trigger scheme on the lower-end models while the (back then) high end DS/MSO4000 uses a "real" analog/hardware trigger which results in very low trigger out delay and jitter. This doesn't reflect the jitter of the trigger event displayed on screen. Since a clever display algorithm can actually shift each and every "accumulated" trace to be displayed, on the time axis so its "statistical center of gravity" meets exactly the trigger point, the resulting trigger jitter can be considered to be one screen pixel. One could argue that the "real" trigger event can be somewhere between two samples of the raw ADC data stream, which is correct in case real time sampling is used. But on repetitive signals with equivalent time sampling, useful sample spacing can be much better. Which is also more or less the case when the display engine sums up a certain number of traces before they are copied to the frame buffer memory (which usually takes place at a much lower rate than at which the waveform acquisition engine fills its memory).

So a specification of trigger jitter may actually be (more or less) irrelevant in case a pure digital (post-processing) trigger engine is used in a particular oscilloscope. It might make sense to specify the Trigger event -> Trigger Out signal delay and jitter in specific cases where this signal needs to be used to synchronize other test gear to the trigger event. This is probably the case only in very few situations. And this is one of the few applications, where the old Rigol DS4000 series is really good at. Otherwise, I'ld only recommend it if it's available at a real bargain and it's shortcomings are really not relevant to the particular application. Just as an oscilloscope, it's not a bad machine though.
 

Offline Performa01

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #36 on: October 02, 2019, 08:28:19 am »
Here you go.

100 KHz 5ns pulse with 2ns risetime, fastest I have from a SDG6022X. Siglent 1 GHz rated BNC cable.
NO clock syncing, just 2 standalone instruments.

Dots and Infinite persistence.


It is quite obvious that there is no visible jitter for a digital trigger system with properly implemented trigger point interpolator and the screenshot with infinite persistence shows just that.

The measurements however, including histograms, work with the raw sample data, which leads to a fairly evenly spread distribution at +/- 1 sample period around the trigger point. So while there is no visual jitter and cursor measurements would be just fine, the standard automatic measurements yield valid results only if the average in the measurement statistics is used.

In case of the SDS5000X, we already have improved measurement strategies for frequency, period, transition time and cycle to cycle jitter. These can provide better resolution and accuracy than the sample period even without averaging. Any attempt to apply this concept universally for all time related measurements as well as horizontal histograms would require a lot of additional processing in many cases, especially considering the deep measurements offered by the current platform.

I don't think the 100ps jitter specification is really meaningful, since I've yet to come across a case where jitter becomes actually visible, even at 200ps/div. This is clearly some worst case specification "by design" and it's a peak value and not RMS on top of that.

That said, there are currently no plans to add an eye-diagram to the SDS5000X series.

 

Offline tv84

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #37 on: October 02, 2019, 08:55:57 am »
Without further derailing the thread, nctnico could you provide some pics of the same diagram created by your several equips that are able to do it? (here or in a eye diagram specific thread) TIA
 

Online Ice-Tea

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #38 on: October 02, 2019, 10:04:13 am »
You know you can get a used machine for a tenth of the price, right?

Online nctnico

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #39 on: October 02, 2019, 11:01:20 am »
Here you go.

100 KHz 5ns pulse with 2ns risetime, fastest I have from a SDG6022X. Siglent 1 GHz rated BNC cable.
NO clock syncing, just 2 standalone instruments.

Dots and Infinite persistence.

But look at the same signal at 100ps/div (if possible) with infinite persistence. You'll see it will get smeared out horizontally.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online tautech

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #40 on: October 02, 2019, 11:24:16 am »
But look at the same signal at 100ps/div (if possible) with infinite persistence. You'll see it will get smeared out horizontally.
500ps/div is all I've got in this 5054X, well tomorrow it might be different.  ;)

I'm inclined to believe Performa01's take on this as he has the 1 GHz model and better equipment to put it through its paces than I. His comments also align with those of TurboTom and reflect what I'm seeing too.
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Online nctnico

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #41 on: October 02, 2019, 01:35:39 pm »
Without further derailing the thread, nctnico could you provide some pics of the same diagram created by your several equips that are able to do it? (here or in a eye diagram specific thread) TIA
I got the same idea but need to find some time first.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline tv84

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #42 on: October 02, 2019, 01:42:12 pm »
I got the same idea but need to find some time first.

Thanks, that would be great. Serve as a comparison reference to these new coming equipments.
 

Offline Performa01

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #43 on: October 02, 2019, 01:59:29 pm »
But look at the same signal at 100ps/div (if possible) with infinite persistence. You'll see it will get smeared out horizontally.
500ps/div is all I've got in this 5054X, well tomorrow it might be different.  ;)

I'm inclined to believe Performa01's take on this as he has the 1 GHz model and better equipment to put it through its paces than I. His comments also align with those of TurboTom and reflect what I'm seeing too.
Just to give you an idea, I’ve dug out a very old SDS5104X screenshot.

Pre-release firmware 0.7.1. No refined measurements yet.
750MHz sine from a high performance synthesizer with OCXO, captured at 200ps/div and displayed in dots mode.
No persistence, but this screenshot still contains some 480 triggered waveforms (acquisitions) – which should be obvious as we still see a contiguous line even though there are only 10 samples per record.

The fact that the resulting trace is so thin without any outliers speaks volumes about trigger stability. One sub-division on the horizontal axis is 40ps and we would be able to spot jitter well below 10ps.
At the end of the day, jitter is practically non-existent.
 
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Online Howardlong

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #44 on: October 02, 2019, 03:57:52 pm »
Depending on what's being measured, the scope may need a PLL to recover the clock for jitter measurements on modern high speed serial buses. If that is the case, make sure the scope has that level of analysis. Typically that also facilitates ways to determine where the jitter is coming from, for example if it's data correlated, or periodic.
 

Online Sighound36

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #45 on: October 02, 2019, 05:41:06 pm »
Depending on what's being measured, the scope may need a PLL to recover the clock for jitter measurements on modern high speed serial buses. If that is the case, make sure the scope has that level of analysis. Typically that also facilitates ways to determine where the jitter is coming from, for example if it's data correlated, or periodic.

Hi Howard

Agree with your above comment 100%

This is the crux of the matter with the latest batch of TEK/R&S/Keysight, etc The scopes that can actually measure these parameters are all priced at £17K + the apps (the less expensive being £4K) add decent active 2Ghz+ probe if you are required to look at power analysis, then the app for this plus a possible high voltage probe plus a decent current probe (at least 1ma sensitive) it really does add up plus vat of coarse (not an issue if you are business which we are)

You really need the ability to have TIE, trends with FFT,  PLL options(clock recovery), at least 2nd order with cornerstone (loop bandwidth) frequency setting ability, plus histogram capability.
With a real time eye diagram with histogram ability. These features are NOT in the basic measurements that come with the 5 series minimum on the big three manufacturers.

Interestingly the Tek MSO54  has a limited bandwidth of 1Ghz in hardware for the 2Ghz option it has to go back service for the actual upgrade, The 6 Series is software crippled upto the 8Ghz max BW limit.

The cost of these 'full analysis apps' range form £4k to £6.2K  :o

This is without the relevant specialist probes.

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Offline 2N3055

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #46 on: October 02, 2019, 06:50:39 pm »
Depending on what's being measured, the scope may need a PLL to recover the clock for jitter measurements on modern high speed serial buses. If that is the case, make sure the scope has that level of analysis. Typically that also facilitates ways to determine where the jitter is coming from, for example if it's data correlated, or periodic.

MSO8000 have basic jitter analysis and eye measurements.
For eye it has: eye height, eye width, eye amplitude, crossing percentage, Q Factor.
For jitter it has: TIE, cycle to cycle, +width to +width, -width to -width
It also have PLL clock recovery.
As I said, somebody needs to test how well it works....
It is not as comprehensive as for instance LeCroy analysis packages, but it is fine for basic verifications.....

 

Online nctnico

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #47 on: October 05, 2019, 12:56:15 am »
Here you go.

100 KHz 5ns pulse with 2ns risetime, fastest I have from a SDG6022X. Siglent 1 GHz rated BNC cable.
NO clock syncing, just 2 standalone instruments.

Dots and Infinite persistence.

It is quite obvious that there is no visible jitter for a digital trigger system with properly implemented trigger point interpolator and the screenshot with infinite persistence shows just that.

I don't think the 100ps jitter specification is really meaningful, since I've yet to come across a case where jitter becomes actually visible, even at 200ps/div. This is clearly some worst case specification "by design" and it's a peak value and not RMS on top of that.
I have given this some thought and I think there is something odd going on here. Look at how the signal converges into a single line near the trigger threshold an then smears out. The image would suggest that the trigger jitter is zero but this can't be true because above and below the trigger point the signal starts to smear horizontally. I have not seen a similar effect on other oscilloscopes. On those I see a signal which keeps about the same width from 20% to 80% of the rise time.
For example:


I think Siglent's trigger interpolator takes a very small part of the signal and uses that to place it at the trigger point which creates a somewhat distorted image. It is even possible the trace smears out more horizontally than when using a larger part of the signal.
« Last Edit: October 05, 2019, 01:15:55 am by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online nctnico

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #48 on: October 05, 2019, 01:08:24 am »
And the same signal (100MHz square wave) on an R&S RTM3004 (click to enlarge to full size):
848530-0
« Last Edit: October 05, 2019, 01:38:21 am by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline blueskull

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Re: 500 MHz+ 4 channel Oscilloscope recommendation. MSO8000 any good?
« Reply #49 on: October 05, 2019, 01:17:29 am »
I also second a Keysight. Been used Keysight scopes for the past half decade, and I won't complain rest of building quality (DOA accessories, firmware rotting, etc.), but service is great, so it's not a big thing to worry about.

I've used Rigol 1052E, 1054Z, 6102, Tek 2024B, 5204B, MDO3054, Owon 7102V, 3102L among other scopes on site or in field. I still prefer Keysight as a daily driver.

Each scope on the above list has unique points, such as the Rigol 1052E and 1054X being cheap, 6102 being fast and cheap, Tek scopes comes with (optional, paid, expensive) high BW current sensors (Tek exclusive) and MDO comes with RF capability, Owon 3102L comes with USB connection (virtual scope).

OTOH, Rigol and Tek are known to be unresponsive, to the point I constantly want to smash them. Owon is just a toy with minimum features and crappy UI (try to single shot and transfer a 10M record length, and the software will hang for a few secs).

When it comes to normal daily use, I still prefer a Keysight for its responsive and easy to use UI.

The memory is short, but I didn't find 512kB bothering me (512kB per channel is what you get at high sample rate with an MSOX6004A). Set your trigger properly, use auxiliary trigger input, and you should be fine.

While the Rigol can be hacked, Keysight sells (relatively) cheap APP bundle, which unlocks all features for a good price, let alone they are also hackable, just not as easy.




                                                   -- From a Keysight scope user and (formal) owner of MSOX3054A, MSOX3104A, MSOX6004A, M9243A and evaluation user of DSOX1204G.
 


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