The Rigol DS1052E

[dimlow]

Dave has taken a break, he posted a note in the "Announcements" forum saying he's going walkabout for a while.  I'm sure the deluge of e-mails and consistent output of quality video blogs has been taxing his time for a while now!

Yea, but that was on the 9th he has posted a new video blog on the 16th so i assumed he was back.

[Mark_O]

You're saying it's 20% slower maximum, but that's actually the minimum.  The maximum would be 600 MS/s slower with both scopes in single channel operation, and 300 MS/s with both scopes in dual channel operation.  That's 50% and 50% maximum difference.  The minimum difference would be 20% with the DS1052E in dual-channel operation and the C model in single channel operation.

Are you talking about using LongMemory, or not?  It's hard to tell.  Personally, I use ShortMemory so infrequently, I hardly remember it's there.    In ShortMemory mode it's 1000M/500MSa, vs. 400M/200MSa, as you say.  In LongMemory mode, it's 500M/250MSa, vs. 400M/200MSa.  That's what I was referring to.  My apologies if I wasn't clear about that.

It's possible you still think the 1000E series will do 500MSa in dual-channel mode, even with LongMemory.  That would be understandable, because that's what Rigol published in their Feb'09 manual for those scopes.  However, they corrected themselves in the Jun'09 edition, and show the correct 250MSa max-rate in Long dual-channel mode.  Try it yourself, and see where it maxes out in dual-channel LongMemory mode.

I do say this makes a huge difference in performance, I operated them side by side to test my modifications and the noise in the C model made the readings far worse than even my 50 MHz unmodified channel.

Yes!, I was very interested in your personal evaluation of the two different models, because I have no E-series unit here to compare my older C-series with.  I wasn't calling your opinion into question at all... just asking because the spec differences are smaller than they initially appear to be.  Thanks for sharing your personal comparisons.

- Mark

[alm]

I'm surprised to hear that Dave made that claim.  Especially since it's not true.  You don't need 10-times oversampling to be able to accurately reconstruct a waveshape.  Assuming a gaussian-distribution (the normal case), you can exactly reconstruct any arbitrary waveform, using sin(x)/x with as little as 2.5x oversampling.  However, to accomplish that requires very good filters (i.e., expensive), and with the quality of filtering on most consumer-grade instruments, you actually need ~4x oversampling to achieve the same results.  (To get technical, it varies, depending on the instrument, from 3-5x... but 4x is a good rule-of-thumb.)

But 10x is really overkill.  Thus even the 400MSa on the earlier 100MHz 1000C-series was perfectly fine.  Based on your claim, they'd only be good to 40 MHz (and the 100 MHz-version of the 1000E would top out at 50 MHz).

One issue with applying the Nyquist-Shannon sampling theory to DSO's is that the theory talks about the total bandwidth of the signal. The bandwidth of an oscilloscope is the -3dB point. The bandwidth in the sampling theory is the highest frequency component. This would require a hard cut-off above 100MHz, as opposed to the Gaussian roll-off that's normal for oscilloscopes. Some of the high-end oscilloscopes, which do oversample less than 10x because they can't make the ADC's and memory fast enough, have a much sharper input filter (there's an Agilent appnote about this). Because your signal may have higher frequency components, you can't treat it like a simple Nyquist reconstruction, so more samples are useful.

[Mark_O]

Ross,

I just went back and reviewed your original comment...
> We have 400 MS/s 100 MHz model C Rigol scopes at school... <

And your more recent:
> I do say this makes a huge difference in performance, I operated them side by side to test my modifications and the noise in the C model made the readings far worse than even my 50 MHz unmodified channel. <

You do realize that the residual noise displayed on the 100MHz model-C will always be higher than on your unmodified 50MHz model-E, simply due to the bandwidth differential?  All other things being equal, wider BW scopes will always exhibit higher apparent noise levels.  That's the nature of the beast, and what we have BW limiting, digital filtering options, averaging, and ET sampling for.  To reduce the contribution of noise, and see the signals underneath.

If the E-series do have less residual noise (which is possible, though the noise-samples Dave posted for his 1052E didn't look significantly different than what I was used to on my 1102CD), it's not a result of higher sampling rates.

Agilent did a paper on noise in digital scopes a while back, and it was quite illuminating.  Even very expensive scopes can exhibit surprisingly high levels of relative noise, under some circumstances as much as 50% of one vertical division on a peak-to-peak basis!  Turn on infinite Persistence, and things can get pretty ugly.  

- Mark

[Mark_O]

One issue with applying the Nyquist-Shannon sampling theory to DSO's is that the theory talks about the total bandwidth of the signal. The bandwidth of an oscilloscope is the -3dB point. The bandwidth in the sampling theory is the highest frequency component. This would require a hard cut-off above 100MHz, as opposed to the Gaussian roll-off that's normal for oscilloscopes. Some of the high-end oscilloscopes, which do oversample less than 10x because they can't make the ADC's and memory fast enough, have a much sharper input filter (there's an Agilent appnote about this). Because your signal may have higher frequency components, you can't treat it like a simple Nyquist reconstruction, so more samples are useful.

Alm, yes, that's correct.  I think the root cause for the confusion was a misinterpretation of what Dave "said".  I was talking about oversampling on the highest-frequency component of a signal.  What Dave, and Simon, and Ross were referring to was evidently the need to sample 10 times per-cycle.  And Dave's right on that... you need a decent number of samples, even with sin(x)/x reconstruction, to be able to capture the higher-order harmonics of a lower-frequency waveform.  No argument there.

- Mark

[Mark_O]

Agilent did a paper on noise in digital scopes a while back, and it was quite illuminating.  Even very expensive scopes can exhibit surprisingly high levels of relative noise, under some circumstances as much as 50% of one vertical division on a peak-to-peak basis!  Turn on infinite Persistence, and things can get pretty ugly.  

They also did a nice job of dispelling the myth that digital scopes are intrinsically "noiser" than analog scopes.  At first look, it seems obvious that the signals on a digital scope are much noiser, but that's attributable mostly to the difference in acquisition and display methods.  I.e., the higher peak-to-peak noise levels you see on your digital scope are captured and displayed instantaneously.  The exact same signal displayed on an analog scope will show much less noise, simply because of the persistence of the phosphor.

I.e., the random peak-to-peak fluctuations don't occur with sufficient frequency to continually repaint on the screen... so you don't see them.  What you do see are those parts of the signal that occur over and over again.  Or in other words, the analog scope has built-in automatic averaging.  Turn averaging on with your Rigol (or any DSO), and see how much cleaner things look!  Almost analog-like.    As little as 4x can make a big difference.

- Mark

[rf-loop]

Mark_O

"...even with sin(x)/x reconstruction..."

My opinion is: Rigol have not this function at all. There is some kind of "smooth" function and nothing else.

Specially this can also see in my some pictures and... I understand they need do also this fake becouse BW is NOT compatible for real or near real Sin(x)/x. 

[Simon]

Agilent did a paper on noise in digital scopes a while back, and it was quite illuminating.  Even very expensive scopes can exhibit surprisingly high levels of relative noise, under some circumstances as much as 50% of one vertical division on a peak-to-peak basis!  Turn on infinite Persistence, and things can get pretty ugly.  

They also did a nice job of dispelling the myth that digital scopes are intrinsically "noiser" than analog scopes.  At first look, it seems obvious that the signals on a digital scope are much noiser, but that's attributable mostly to the difference in acquisition and display methods.  I.e., the higher peak-to-peak noise levels you see on your digital scope are captured and displayed instantaneously.  The exact same signal displayed on an analog scope will show much less noise, simply because of the persistence of the phosphor.

I.e., the random peak-to-peak fluctuations don't occur with sufficient frequency to continually repaint on the screen... so you don't see them.  What you do see are those parts of the signal that occur over and over again.  Or in other words, the analog scope has built-in automatic averaging.  Turn averaging on with your Rigol (or any DSO), and see how much cleaner things look!  Almost analog-like.    As little as 4x can make a big difference.

- Mark

I beg to differ my rigol is noisy and the only way to cure it is use the inernal filtering and hope you don't have to measure in the same band as the noise

[Mark_O]

I beg to differ my rigol is noisy and the only way to cure it is use the inernal filtering and hope you don't have to measure in the same band as the noise

So you're saying you've tried averaging, and it did no good?

- Mark

[DJPhil]

For those of you looking for Dave, he's on walkabout for a while.

I'm sure when he gets back he'll do all his catching up and you'll hear from him.

[miki]

I haven't noticed in any of the screenshots whether users that made the DS1052->DS1102 mod are able to achieve 2 ns/div on the horizontal scale?
What about equivalent sampling, is this also increased from 10 to 25 GSa/s?

Thanks.

[flolic]

I connected pulse generator directly to the scope and there is no ringing any more 

[KTP]

I just caught this thread...I purchased a DS1052E four months ago after reading the EEVblog reviews of it.  I knew if I went away for awhile and came back you guys would figure out a way to "upgrade" it.  Bravo! 

So I need to construct a null modem RS232 cable and then type some stuff in hyperterminal?  Sounds too easy.

[rf-loop]

Also if horizontal is 2ns/div and mode is egualtime (oka: repetitive) it is 25Gs/s

So, just as 1102.


Also of course original 1102 can move to 1052 and it works just as original 1052. (BW limits, 2ns/s // 25Gs/s equ is out. (25Gs equ is only with 2ns/div)

[KTP]

Ok that was too easy. 

A couple of things.

It is a straight through serial cable, not null  modem.

You have to send commands by holding alt and pressing "0","1","0" (this took me a bit to figure out)

My DS1052E now displays 2ns per division even after power cycle, and *IDN? says it is a DS1102E 

Running the self calibration now.

Thanks guys

[Mastro Gippo]

Damn, the post notification mail didn't work, and I discovered the news just today!
I just made the mod myself, and IT WORKS GREAT!! Thanks everyone... I should add a few info about my experience:
The correct method is to changhe the serial number first, then the model number, then you can power cycle the scope. Keep your fingers away from the "enter" key!! If you press it instead of the alt+010 combination, it will add a line return at the end of the serial number. Always double check the results of the query commands before power cycling.

My father did some tests with a professional signal generator, you can see the data and graphs in the attached document. Somehow excel won't let me set the horizontal scale to logarithmic, so I left everything as-is.
I'm happy!  

[Dynomo]

Damn, the post notification mail didn't work, and I discovered the news just today!
I just made the mod myself, and IT WORKS GREAT!! Thanks everyone... I should add a few info about my experience:
The correct method is to changhe the serial number first, then the model number, then you can power cycle the scope. Keep your fingers away from the "enter" key!! If you press it instead of the alt+010 combination, it will add a line return at the end of the serial number. Always double check the results of the query commands before power cycling.

My father did some tests with a professional signal generator, you can see the data and graphs in the attached document. Somehow excel won't let me set the horizontal scale to logarithmic, so I left everything as-is.
I'm happy!  

I did the model number then the serial number, worked fine that way round for me. I was swapping back and forth between 100mhz to 50mhz doing some testing and accidently left the E off the model number and the scope still booted up fine to my surprise. I never noticed I have left the E off the model number until I looked at the scope wondering why the model number was wrong It fired up with DS1102 as 100mhz ok luckily.

[Mark_O]

I connected pulse generator directly to the scope and there is no ringing any more 

That's really great to see, thanks.  Very impressive performance.

- Mark

[DJPhil]

you can see the data and graphs in the attached document.

Thanks for the procedure details.

I just wanted to include a short bit for those who don't speak Italian and may be confused by the bottom two graphs in the spreadsheet.

Canale = Channel
Differenza misura frequenza = frequency difference measurement

[rf-loop]

..some tests with a professional signal generator....

I take partial picture about this test xls to here. I hope Mastro Gippo accept this copy. (in copy read source info)



I want ask: What are numbers in Y scale? (My quess (becouse these shown numbers) is that they are scope measured RMS and if they are, please connect this 50ohm terminator and test agen ). Sig gen output is for 50ohm load.)

What are oscilloscope settings in this measure. Same settings in whole frequency scale? (scope mV/div, equtime or realtime? x ns/div? normal memory? Sinx/x on/off?)
What is signal  exactly connection to oscilloscope inputs.  (cable type/termination? calibration or some opinion how accurate leveling over used freq range = also if it is R&S it may be fail.)

If I or somebody tell data/numbers but not tell how I get data/numbers they are nearly or just as garbage...

I ask becouse there is something wrong!
there is minimum 3 posibilities:

1. Test configuration is bad? (bad cable/missing or fail termination.)
2. Your oscilloscope is fail. (not my first opinion becouse both channels equal)
3. Signal generator is fail. (leveling defect)

If all is ok with test: 1052Emod or 1102E frequency response (flatness) is never as bad as in picture. If picture freq response is true for these scopes they are just as toys or garbace stuffs. (but they are not if they work normally)

But in real: Simple, I think test configuration fails

[flolic]

I was swapping back and forth between 100mhz to 50mhz doing some testing and accidently left the E off the model number and the scope still booted up fine to my surprise. I never noticed I have left the E off the model number until I looked at the scope wondering why the model number was wrong It fired up with DS1102 as 100mhz ok luckily.

What makes me think, maybe we should try to rename the scope as DS1152E or DS1202E and get even more from it 

[flolic]

I ask becouse there is something wrong!
there is minimum 3 posibilities:

1. Test configuration is bad? (bad cable/missing or fail termination.)
2. Your oscilloscope is fail. (not my first opinion becouse both channels equal)
3. Signal generator is fail. (leveling defect)

My vote goes for a number 1 

[JimBeam]

What makes me think, maybe we should try to rename the scope as DS1152E or DS1202E and get even more from it  

Or maybe 1204D, and suddenly two additional BNC and a SCSI like connector blossom up on the front  

[flolic]

P.S.  BTW, I wanted to say "thanks" for those exceptional detailed photos you did of the Rigol internals.  The combined panoramic shots were phenominally good, and extremely well lit.  Really amazing.  Thanks!

Haha, I tried my best  
Also, I am sure that you would not believe me when I tell you that only lighting was from my flashlight  

[flolic]

Or maybe 1204D, and suddenly two additional BNC and a SCSI like connector blossom up on the front  

Mmmm, I definitely have to try that