Author Topic: New Rigol DS1054Z oscilloscope  (Read 2042595 times)

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Offline miguelvp

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Re: New Rigol DS1054Z oscilloscope
« Reply #375 on: October 13, 2014, 09:54:43 am »
Yeah, but where is my logic analyzer????

It has options for serial decoding, trigger on serial events/serial data, etc.

It was a tongue in cheek comment. It's just $400!

Most everyone's phones cost as much as that!
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #376 on: October 13, 2014, 11:15:28 am »
Agreed.  That's why it is such a shame that the main thread dedicated to what is probably the best oscilloscope buy in quite a few years has been polluted with irrelevant and unhelpful noise.  Perhaps the thread could be tidied up so it can add value long into the future ?

Threads don't get "tidied up" here - although you can go back and delete your own comments from it. OTOH, you can also start another thread at anytime - for that long-term, future-value appeal (whatever that might amount to in the 21st century).  :)
 

Offline EEVblog

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Re: New Rigol DS1054Z oscilloscope
« Reply #377 on: October 13, 2014, 11:36:32 am »
Agreed.  That's why it is such a shame that the main thread dedicated to what is probably the best oscilloscope buy in quite a few years has been polluted with irrelevant and unhelpful noise.  Perhaps the thread could be tidied up so it can add value long into the future ?

Forum are not, and never will be repositories of filtered information. They simply don't work like that.
You can force that information through "tidying up", but then the forum dries up and dies because that's not what people come here every day for.
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #378 on: October 13, 2014, 11:42:26 am »
One could argue that if you planned to return it from the get go that that might not be so ethical.

I'd certainly argue that. The seller will have a hard time selling it as "new" if it's had 30 days use (especially since the DS1054Z has trial features that tick away as you use it).

The seller will likely have more than a hard time doing this in most places.  At best it will be an "open box" item or "recertified" or "refurbished" but selling it as "new" would be unlawful.  It sometimes happens anyway of course and sometimes sellers get caught doing it.

I have never purchased something for sale with the intention of borrowing it for no matter how short a duration and then returning it for a refund although I know people who have.  Yes, I could always make up some reason as justification for returning it but the basic dishonesty of doing this would haunt me.
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #379 on: October 13, 2014, 01:28:48 pm »
...but the basic dishonesty of doing this would haunt me.

I see your point, David - OTOH, I'm not sure why you think making continual speculations in this thread (without any proof) that Rigol is deliberately taking steps to hide errors in this DSO is much better.

I would be the first to admit that companies (and, unfortunately, often Chinese companies) are sometimes misleading - or not forthcoming - about problems/faults in their products (and Rigol is certainly no exception). And I have definitely questioned the veracity of posted specifications myself in this forum - but I've tried to do it based on conflicting or contrary (or, admittedly :-[, sometimes misunderstood) information/evidence related to the product itself - rather than history.

So unless/until you have some corroboration that supports your speculations, perhaps you might give them the benefit of the doubt? When I originally suggested you buy one and test it, I was fairly sure you would find yourself impressed by the value for money (even given it's shortcomings) - and end up keeping it in the end.  :)

- Mark
« Last Edit: October 13, 2014, 01:32:00 pm by marmad »
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #380 on: October 13, 2014, 02:19:48 pm »
Getting back to more practical information: it would be good if an owner with the necessary test gear charted the frequency response of the DSO before implementing the 100MHz BW option (or after removing it).

As mentioned before, it's fairly easy to turn ON/OFF the 100MHz BW option with SCPI commands, and if the 50MHz BW device had a sharp enough roll-off implemented in the front-end (i.e. attenuating >= 125MHz >= -12db), it would be an alternative way to BW limit the device when using primarily 3/4 channels (while keeping the working BW around the stated 50MHz maximum).

Since Rigol has eliminated the LMH6518 in the DS1000Z (I assume to cut costs since it's a fairly expensive device), even better would be knowing precisely what they're doing in the front-end to control the low-pass filter - both for model differentiation and/or channel BW limiting. Maybe Dave can play around with that during a teardown.
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #381 on: October 13, 2014, 02:25:07 pm »
...but the basic dishonesty of doing this would haunt me.

I see your point, David - OTOH, I'm not sure why you think making continual speculations in this thread (without any proof) that Rigol is deliberately taking steps to hide errors in this DSO is much better.

In my previous experiences with Rigol, I concluded that they were systematically deceptive about the capabilities of their DSOs.  In reality, maybe they were just incompetent but how does one tell the difference?  The result is the same in either case.

Once is happenstance. Twice is coincidence. Three times is enemy action.

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I would be the first to admit that companies (and, unfortunately, often Chinese companies) are sometimes misleading - or not forthcoming - about problems/faults in their products (and Rigol is certainly no exception). And I have definitely questioned the veracity of posted specifications myself in this forum - but I've tried to do it based on conflicting or contrary (or, admittedly :-[, sometimes misunderstood) information/evidence related to the product itself - rather than history.

I try to pick on all companies when they do this in an equal opportunity way.  Tektronix is often an object of my derision.  I admit to having more than my fair share of cynicism.

As far as direct experience, I briefly evaluated several Rigol oscilloscopes before the DS1000Z and DS2000A series were released so this was years ago.  I concluded then that a 20+ year old Tektronix 2230 or 2232 was a better value but readily admit that this would not be the case for most users and so tend to recommend the DS1000Z series if asked despite my misgivings about Rigol in general.

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So unless/until you have some corroboration that supports your speculations, perhaps you might give them the benefit of the doubt? When I originally suggested you buy one and test it, I was fairly sure you would find yourself impressed by the value for money (even given it's shortcomings) - and end up keeping it in the end.  :)

I have pointed to evidence others have published (even Rigol) which you have not addressed so I hardly believe at this point that you would consider direct evidence produced by me.

I have considered doing what you suggest (but was rather taken aback that you suggested buying one for evaluation with the intention of returning it) but neither of the Rigol DSOs I might consider will do anything significant for me that I cannot already do with my existing analog and digital oscilloscopes and they lack what I would consider a killer feature like support of network analysis by returning FFT phase information.

Apparently their waveform reconstruction and triggering is defective at least by my standards but I will disagree with you on that until I get to test one or someone posts some relevant test results. :)

It bothers me that we do not agree but please do not take it personally.
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #382 on: October 13, 2014, 03:03:26 pm »
I have pointed to evidence others have published (even Rigol) which you have not addressed so I hardly believe at this point that you would consider direct evidence produced by me.

You seem to have a strange idea as to what constitutes "evidence" of something. If I post links to documents reporting that some bridges collapse, this does not prove - to any degree whatsoever - that the bridge located next to your house has or will collapse.

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..but neither of the Rigol DSOs I might consider will do anything significant for me that I cannot already do with my existing analog and digital oscilloscopes

So I'm curious: what DSO do you own that can capture up to 65000 separate waveforms for decoding or analysis, over a span of time from microseconds to days?   :)

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Apparently their waveform reconstruction and triggering is defective

No, I think you're confused about the meaning of "apparently" (as with "evidence" above :)). Their waveform reconstruction and triggering in the UltraVision DSOs appears to be fine - unless someone proves otherwise with tests.
« Last Edit: October 13, 2014, 03:33:58 pm by marmad »
 

Offline edavid

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Re: New Rigol DS1054Z oscilloscope
« Reply #383 on: October 13, 2014, 03:45:44 pm »
Getting back to more practical information: it would be good if an owner with the necessary test gear charted the frequency response of the DSO before implementing the 100MHz BW option (or after removing it).

Stan Perkins did that:

https://www.eevblog.com/forum/testgear/new-rigol-ds1054z-oscilloscope/msg523785/#msg523785

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Before the "upgrade" I measured the bandwidth as almost exactly 50 MHz with a sharp rolloff above 50 MHz, consistent with bandwidth limiting in software.
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #384 on: October 13, 2014, 04:43:07 pm »
Stan Perkins did that:

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Before the "upgrade" I measured the bandwidth as almost exactly 50 MHz with a sharp rolloff above 50 MHz, consistent with bandwidth limiting in software.

I saw that post, but it's a bit vague. He doesn't specify the slope of the roll-off (specifically, the attenuation at 125MHz), and he mentions that he believes it's being done in software - although this would be a different method than Rigol has used in the past (at least, it's different than the DS2000 - perhaps the DS1052E/DS1102E also uses software limiting?).

EDIT: Also, there has been at least one conflicting report to Stan's posted here.
« Last Edit: October 13, 2014, 04:56:25 pm by marmad »
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #385 on: October 13, 2014, 05:59:02 pm »
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..but neither of the Rigol DSOs I might consider will do anything significant for me that I cannot already do with my existing analog and digital oscilloscopes

So I'm curious: what DSO do you own that can capture up to 65000 separate waveforms for decoding or analysis, over a span of time from microseconds to days?   :)

I have a Tektronix 7834 analog storage oscilloscope for making 4 channel 300 MHz captures at 250,000+ sweeps per second (but not at the same time) over a span of seconds to minutes.  Technically it can go for hours but it is already difficult enough to use and bistable storage mode is painful on the eyes.  I have a pair of 2230s for making 4 channel captures over hours to days if necessary.  I have never needed to do serial protocol analysis beyond what my word recognizer will support with a little help because my serial interface designs always work and I have other debugging methods available if necessary.  Signal integrity does not require protocol analysis.

The serial decoding and MSO capabilities are the features I would consider the Rigol oscilloscopes for but I have not needed them yet.  I could have used a DSO which returns FFT phase information in the past but practically nobody supports that anymore.

My go-to DSO is a 2230 or 2232.  It just depends on which is closer.

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Apparently their waveform reconstruction and triggering is defective

No, I think you're confused about the meaning of "apparently" (as with "evidence" above :)). Their waveform reconstruction and triggering in the UltraVision DSOs appears to be fine - unless someone proves otherwise with tests.

I argued that they were both fine.  I was told that they were not.
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #386 on: October 13, 2014, 06:00:59 pm »
Stan Perkins did that:

Quote
Before the "upgrade" I measured the bandwidth as almost exactly 50 MHz with a sharp rolloff above 50 MHz, consistent with bandwidth limiting in software.

I saw that post, but it's a bit vague. He doesn't specify the slope of the roll-off (specifically, the attenuation at 125MHz), and he mentions that he believes it's being done in software - although this would be a different method than Rigol has used in the past (at least, it's different than the DS2000 - perhaps the DS1052E/DS1102E also uses software limiting?).

EDIT: Also, there has been at least one conflicting report to Stan's posted here.

Bah.  I was going to mention the conflicting report (if I could find it) but you got to it before I finished my other reply. :)
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #387 on: October 13, 2014, 06:50:14 pm »
I have a Tektronix 7834 analog storage oscilloscope for making 4 channel 300 MHz captures at 250,000+ sweeps per second (but not at the same time) over a span of seconds to minutes.  Technically it can go for hours but it is already difficult enough to use and bistable storage mode is painful on the eyes.  I have a pair of 2230s for making 4 channel captures over hours to days if necessary.

Neither of these have anything close to the storage capabilities of the DS1000Z or DS2000. The 7834 is limited (according to it's datasheet) to 30 minutes of time, and the 2230's can save a maximum of 3 waveforms (each @ 1k compressed). There is simply no way you can, for example, capture and store a 14k waveform once per second for 18 hours.
« Last Edit: October 13, 2014, 06:52:51 pm by marmad »
 

Online Fungus

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Re: New Rigol DS1054Z oscilloscope
« Reply #388 on: October 13, 2014, 07:04:57 pm »
I saw that post, but it's a bit vague. He doesn't specify the slope of the roll-off

"Sharp"

and he mentions that he believes it's being done in software - although this would be a different method than Rigol has used in the past (at least, it's different than the DS2000 - perhaps the DS1052E/DS1102E also uses software limiting?).

Software makes sense. I assume they made no hardware modifications to the existing DS1074Z/DS1104Z 'scope.

PS: The 'scope already has a 20MHz bandwidth limiter button. Does anybody know if that's that hardware, software, FPGA...? Maybe they re-used that as a 50MHz limiter.

 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #389 on: October 13, 2014, 07:33:04 pm »
"Sharp"
He doesn't specify the slope of the roll-off (specifically, the attenuation at 125MHz)

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Software makes sense. I assume they made no hardware modifications to the existing DS1074Z/DS1104Z 'scope.

It wouldn't matter if there was already a control method of adjusting the cut-off frequency for that BW in the front-end - just as Rigol didn't have to alter the front-end of the DS2000A to accommodate the 300MHz model when it was released.
« Last Edit: October 13, 2014, 07:39:52 pm by marmad »
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #390 on: October 13, 2014, 08:31:49 pm »
I have a Tektronix 7834 analog storage oscilloscope for making 4 channel 300 MHz captures at 250,000+ sweeps per second (but not at the same time) over a span of seconds to minutes.  Technically it can go for hours but it is already difficult enough to use and bistable storage mode is painful on the eyes.  I have a pair of 2230s for making 4 channel captures over hours to days if necessary.

Neither of these have anything close to the storage capabilities of the DS1000Z or DS2000. The 7834 is limited (according to it's datasheet) to 30 minutes of time,

The Tektronix specifications are pessimistic (*) but storage time in bistable mode, which I would hate to use for the reason I gave, lasts essentially until power is removed and oddly enough generally even after that; that may seem a little odd but analog storage CRTs are weird.  In reality I would never use persistence longer than a few minutes deliberately but it is handy for fast glitch hunting and as a variable persistence sampling display which is what I mostly use it for.

The DS2302A has almost the same bandwidth, the 7834 can be configured as fast as 400 MHz but the difference is not significant, but costs more than every oscilloscope I have combined without replacing the capabilities of all of them.

I would never recommend a 7834 to someone unless they had a specific requirement that it filled which modern but cheap DSOs did not and even then I would try to find an alternative.  That is a very short list even if you include various ways a 7834 may be used to crush invaders. :)

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and the 2230's can save a maximum of 3 waveforms (each @ 1k compressed). There is simply no way you can, for example, capture and store a 14k waveform once per second for 18 hours.

Or one channel with a 4k record length or 2 channels with 2k record lengths and half of those again if peak detection is used.  They can actually store lots of waveform but that requires the memory backup option.  These oscilloscopes also support external clocking for arbitrarily long duration recording but I have never needed it.  If I am hunting for something specific over a long period of time, I would be using a qualified trigger circuit of some sort which Rigols are better at.  If I am not sure of what I am looking for, I would have to rely on envelope detection and again, the Rigols would probably perform better for this but I am no longer sure.

None of them can capture and store a 14k waveform once per second for 18 hours but there are many things the Rigols cannot do that these can and they are the things I require.  I keep being told that the Rigols are incapable of measuring the things I would like including for instance RMS jitter to high resolution or high resolution jitter at all.  That is something I could use.  I can do it now even within a 100 MHz bandwidth but it is not as convenient as it could be.

(*) Tektronix at the time was routinely pessimistic in their specifications even for marketing.  They would generally list the minimum guaranteed number like 500 MHz for an oscilloscope which typically was more like 700 MHz or 600 picoseconds for pulse generator which actually performs more like 450 picoseconds.  The 30 minute time for the 7834 variable persistence storage display probably reflects the amount of patience someone had watching it to make sure it met the specification they promised.  The same statement could be made about transistor leakage or operational amplifier input bias current or noise.  Testing takes time and costs money.
 

Offline pa3bca

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Re: New Rigol DS1054Z oscilloscope
« Reply #391 on: October 13, 2014, 09:00:41 pm »
I don't have the equipment to produce a clean sine wave close to 1GHz/500MHz (my DS2000's 1/2 channel Nyquist frequencies) - but even if I did, I'm not sure why I would spend time running tests to satisfy your (and your's alone, as far as I've read) suspicions.

Hmm well I can generate sigs up to 1.5 GHz with my DSA815 so I did some tests with my "upgraded" 1074Z with 4 channels on, so 250 MSa/s:
100 to 200 MHz.
Nice aliassing! notable the 200 MHz in, resulting in a 50 MHz displayed sine...  (250-200 = 50, so the math checks out  :P)
The HW counter loses it above 100 MHz, until it folds back to < 100 MHz...

100MHz:


120 MHz:


160 MHz:


200 MHz:

« Last Edit: October 13, 2014, 09:04:51 pm by pa3bca »
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #392 on: October 13, 2014, 09:09:27 pm »
That is a very short list even if you include various ways a 7834 may be used to crush invaders. :)

 ;D

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...but there are many things the Rigols cannot do that these can and they are the things I require.
 
No argument there - I was just trying to specify at least one way in which these new, cheap, deep-memory DSOs can outperform some of the great, older gear. I still keep and use my 35-year old Tek 212 - even though it only has a BW of 500kHz - because manufacturers still don't make inexpensive, lightweight, battery-operated, double-insulated (floating to 600V) DSOs - although they're getting closer.
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #393 on: October 13, 2014, 09:20:39 pm »
Hmm well I can generate sigs up to 1.5 GHz with my DSA815 so I did some tests with my "upgraded" 1074Z with 4 channels on, so 250 MSa/s:
100 to 200 MHz.
Nice aliassing! notable the 200 MHz in, resulting in a 50 MHz displayed sine...  (250-200 = 50, so the math checks out  :P)

I think the 100 MHz example is displaying aliasing in the digitizer like I described but the variable persistence is concealing it as a thicker trace.  The 120 MHz example definitely shows a problem but it is so extreme that I am not sure if something else is going on.  The 160 MHz example shows what I expected the 100 MHz example to look like.  The 200 MHz example actually looks like the best of the bunch to me.

Only the 120 MHz results looks weird to me but I think I know what causes it in this case.  I have seen something similar which appeared to be related to the aperture time of the digitizer implying a non-linear frequency response but I do not think that is it.

Since these oscilloscopes have FFT support, they should be able to display their digitizer non-linearity and sampling errors directly as harmonic and non-harmonic distortion products as shown in that Agilent application note I linked.
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #394 on: October 13, 2014, 09:30:32 pm »
Hmm well I can generate sigs up to 1.5 GHz with my DSA815 so I did some tests with my "upgraded" 1074Z with 4 channels on, so 250 MSa/s:
100 to 200 MHz.
Nice aliassing! notable the 200 MHz in, resulting in a 50 MHz displayed sine...  (250-200 = 50, so the math checks out  :P)
The HW counter loses it above 100 MHz, until it folds back to < 100 MHz...

Thanks for these! Any chance you could do them one more time with sin(x)/x OFF (linear interpolation ON) just for a comparison? Perhaps it doesn't make much difference with a simple sine wave at 5 pts/div; you might try a set at the smallest timebase as well.

I think the 100 MHz example is displaying aliasing in the digitizer like I described but the variable persistence is concealing it as a thicker trace.  The 120 MHz example definitely shows a problem but it is so extreme that I am not sure if something else is going on.  The 160 MHz example shows what I expected the 100 MHz example to look like.

The 100MHz example is the only one captured while the DSO is running - meaning a snapshot from the intensity buffer while capturing >10,000 waveforms per second. When the DSO is stopped, it's just the last captured waveform - as seen in the other 3 images.
« Last Edit: October 13, 2014, 09:32:53 pm by marmad »
 

Offline pa3bca

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Re: New Rigol DS1054Z oscilloscope
« Reply #395 on: October 13, 2014, 09:40:45 pm »
Thanks for these! Any chance you could do them one more time with sin(x)/x OFF (linear interpolation ON) just for a comparison? Perhaps it doesn't make much difference with a simple sine wave at 5 pts/div; you might try a set at the smallest timebase as well.
See attachments.
Waveforms look about the same, only the amplitudes are significantly lower.

I think the 100 MHz example is displaying aliasing in the digitizer like I described but the variable persistence is concealing it as a thicker trace.  The 120 MHz example definitely shows a problem but it is so extreme that I am not sure if something else is going on.  The 160 MHz example shows what I expected the 100 MHz example to look like.

The 100MHz example is the only one captured while the DSO is running - meaning a snapshot from the intensity buffer while capturing >10,000 waveforms per second. When the DSO is stopped, it's just the last captured waveform - as seen in the other 3 images.
Yup, correct. An oversight here. A single capture @ 100 MHz shows a "thin" trace like the others.
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #396 on: October 13, 2014, 09:45:30 pm »
That is a very short list even if you include various ways a 7834 may be used to crush invaders. :)

 ;D

I have a scope cart so it does not crush me if I have to move it. :)

The only thing I find lacking about the 7834 within its limitations is the brightness and clarity of its CRT, it could be considered dim and fuzzy, but all storage CRTs suffer from this problem compared to non-storage CRTs and I did not even notice it until I used a 7904 which is effectively the non-storage version and looks absolutely amazing.

Quote
Quote
...but there are many things the Rigols cannot do that these can and they are the things I require.

No argument there - I was just trying to specify at least one way in which these new, cheap, deep-memory DSOs can outperform some of the great, older gear. I still keep and use my 35-year old Tek 212 - even though it only has a BW of 500kHz - because manufacturers still don't make inexpensive, lightweight, battery-operated, double-insulated (floating to 600V) DSOs - although they're getting closer.

And I just picked one way that they do not meet my needs. :)

I understand the utility of deep memory and have used such DSOs in the past but not because of their deep memory capability.  It is vital for some types of measurements and protocol decoding in certain cases and of course more is always better as long as you do not have to always use it or pay for it.

I think I remember seeing the marketing ads for the Tektronix 212 and its cousins but they were basically before my time and to me they always looked a little weird.

Electrical safety is often underrated by those who should know better.  Aren't oscilloscopes like the Tektronix TPS series close replacements?  I thought I remembered seeing a similar Rigol or Siglent but now I just find the handheld Siglent SHS1000 series.  I used to use an early Fluke Scopemeter but it was neither isolated except for being battery powered and it was hard on the eyes.
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #397 on: October 13, 2014, 10:06:13 pm »
I think the 100 MHz example is displaying aliasing in the digitizer like I described but the variable persistence is concealing it as a thicker trace.  The 120 MHz example definitely shows a problem but it is so extreme that I am not sure if something else is going on.  The 160 MHz example shows what I expected the 100 MHz example to look like.

The 100MHz example is the only one captured while the DSO is running - meaning a snapshot from the intensity buffer while capturing >10,000 waveforms per second. When the DSO is stopped, it's just the last captured waveform - as seen in the other 3 images.

Yup, correct. An oversight here. A single capture @ 100 MHz shows a "thin" trace like the others.

Hmm.  I was going to say you found evidence of the problem I suspected (which is not really a problem unless it affects triggering) but after becoming suspicious of my conclusions and reviewing the DSA815 tracking generator specifications, I do not think it will work for the measurement I had in mind because of its high levels of distortion which are irrelevant in tracking generator applications.

https://www.eevblog.com/forum/testgear/rigol-dsa-815-tracking-generator-distortion/
 

Offline alank2

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Re: New Rigol DS1054Z oscilloscope
« Reply #398 on: October 13, 2014, 10:52:07 pm »
So, if I am understanding the traces:

100 MHz - ok
120 MHz - showing signs of a problem, getting bigger and smaller amplitude
160 MHz - aliasing to 80 MHz
200 MHz - aliasing to 50 MHz

Just out of curiosity, what would this test look like with a square wave?
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #399 on: October 14, 2014, 02:36:45 am »
So, if I am understanding the traces:

100 MHz - ok
120 MHz - showing signs of a problem, getting bigger and smaller amplitude
160 MHz - aliasing to 80 MHz
200 MHz - aliasing to 50 MHz

They show exactly what you would expect given that the source has a high level of distortion; tracking generators do not have to be clean.  The test in this case is not significant except on a gross scale and does not say anything useful about the DSO.

Quote
Just out of curiosity, what would this test look like with a square wave?

I would like to know that myself but only a fast edge is really necessary.
 


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