Yeah, but where is my logic analyzer?
It has options for serial decoding, trigger on serial events/serial data, etc.
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 ?
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 ?
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).
...but the basic dishonesty of doing this would haunt me.
...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.
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.
..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
Apparently their waveform reconstruction and triggering is defective
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).
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.
Stan Perkins did that:QuoteBefore the "upgrade" I measured the bandwidth as almost exactly 50 MHz with a sharp rolloff above 50 MHz, consistent with bandwidth limiting in software.
Quote..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?
QuoteApparently 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.
Stan Perkins did that:QuoteBefore 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.
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 saw that post, but it's a bit vague. He doesn't specify the slope of the roll-off
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?).
"Sharp"
He doesn't specify the slope of the roll-off (specifically, the attenuation at 125MHz)
Software makes sense. I assume they made no hardware modifications to the existing DS1074Z/DS1104Z 'scope.
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.
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.
That is a very short list even if you include various ways a 7834 may be used to crush invaders.
...but there are many things the Rigols cannot do that these can and they are the things I require.
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 )
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 )
The HW counter loses it above 100 MHz, until it folds back to < 100 MHz...
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.
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.
That is a very short list even if you include various ways a 7834 may be used to crush invaders.
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.
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.
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?