Author Topic: The Rigol DS1052E (Read 644982 times)

rossmoffett · « **Reply #175 on:** February 15, 2010, 08:19:45 am »

Those are in-circuit measurements - I just measured the caps (I kept them) out of circuit and mine are ~160 pF too. Doh! There must be something else around to limit bandwidth.. unless you have different size inductors, or maybe there is something behind those vias.

That ADC driver could be a bandwidth limiter, if I could find a match for it. It's not an 8-lead TSSOP as I posted earlier, I looked closer in zoom images and it seems to be a 10 pin no-lead chip of some sort. It's so hard to tell, they're tiny! I still can't find it from Analog Devices, though it must be one of theirs based on the Analog sandwich around it. I imagine it's classified as a differential op-amp, but I can't find it in that category yet. It's approximately 2.6 x 2.9 mm (+/- .1 mm) based on the photographs, I found that by comparing to known parts data.

Don't worry about re-installing the filter - if you read the datasheet on the page that I mentioned it notes that the filter is only necessary depending on application. At least, I think. The only use those capacitors could have is to hold a voltage stable, but I don't see how that could be necessary.

Given that you have a 100 MHz scope, you should only see marginal improvements at 125 MHz. There will be a sharp dropoff following that, though. If you have anything that will generate 100 MHz, check to see what V1/V2 is there. It should be .7 if channel 2 is of a sufficiently higher bandwidth, as you can see where I posted V1/V2 at 50 MHz. From my graphs above, you can also see that my good luck starts to end at about 130 MHz. That's where the modified channel gain starts losing ground to the unmodified channel. In the app notes for the ADC there's nothing else stopping the signal but the ADC driver, so that may be the next place to look, unless someone finds some filter before the variable gain amplifier.

jahonen · « **Reply #176 on:** February 15, 2010, 09:51:19 am »

Quote from: rossmoffett on February 15, 2010, 06:31:20 am

I'm not sure what's going on here, Channel 1 seems to be picking up the transients now. Maybe I had a poor connection when I took the earlier measurement.

That looks like spurious oscillation. For easy bandwidth check, a high-edge rate digital (repetition frequency can be set to very low frequency, say, 1 kHz) signal is a easy check. One should see rise or fall time of about 0.35/BW if everything is ok. For 100 MHz that translates to 3.5 ns etc. If the rise time is not reduced, then the effective bandwidth for practical measurements is not going to be very significant.

You can get fast edges from just about any digital chip, except from that old 4000-series CMOS. Even old PIC16F877 seems to have about 160 MHz bandwidth (without any other additional loading than scope probe), see here. That contains some probing hints also

Regards,
Janne

rossmoffett · « **Reply #177 on:** February 15, 2010, 10:10:49 am »

I understand spurious oscillation, it's just that the earlier post I made was observing a 1 MHz square wave under identical conditions and the unmodified channel failed to pick up all of the intricacies. I believe I must have not grounded the probe properly the first time around. Thanks, though!

OK, I think I have narrowed down what kind of chip the ADC driver is. I thought I saw an extra pad on one of Dave's close-ups, which would have explained why I couldn't find an 8-lead package, but upon close inspection from top views I can't see that it would be the case. Browsing the ADC drivers at the Analog Devices website seemed futile, until I checked a supplier. These chips are available in packages not described on the AD website. I noticed that the screen print around the part seems to be 3x3 mm. This leads me to believe they must have some oddball part, but the PCB still looks like it would fit these two parts, which come with the squared edges.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=AD8350ARMZ20-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=AD8132ARMZ-ND

They are 900 MHz and 350 MHz respectively. I'll have to crack it open again and take some measurements on gain and voltage to be sure which part it is, still could be any of the other 8 pin parts. The version with the worst (feasible) bandwidth is the AD8137, with a bandwidth of 110 MHz. The only lower ones clock at 38 and 30 MHz. I can find it in a package with bevelled edges in 3x3 mm, but not with the square ones.

and.. here's the AD8138 in the package that's in the scope:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=AD8138ARMZ-ND

A 320 MHz part.

rossmoffett · « **Reply #178 on:** February 17, 2010, 10:25:15 am »

Quote from: flolic on February 15, 2010, 07:35:05 am

Yes, I modified second channel on my 1102E last night. I removed both (HI & LO) caps, btw. they are 160pF on my scope. I don't have any function/signal generator that go beyond 100MHz range, so I used old FM tuner and pick up signal from local oscillator set up at 125MHz.

It seems that mod did not do anything to my scope, signal amplitude on modified channel is just marginally better than unmodified. I used standard probes. Today I will buy some BNC connectors and coax and make high bandwidth 50 ohm terminated probe.

But I noticed another thing when measuring complex signal (square wave, 32MHz xtal osc. and 200kHz osc. with joined outputs). On modified channel you can clearly see higher components of a signal, in a 250MHz range! So it seems that mod is actually working
Just hope that that is real signal and not some kind of aliasing or ringing...

I took mine apart again in light of your not noticing much difference. My digital camera still has a broken screen but I used it to take some pictures anyway, they're of pretty low quality or I'd post them. I made a quick-flash gif between my scope and yours, I can't find a single component difference! Those inductors hanging off of the caps that we removed are different values on Dave's scope, but not on mine.

I flipped to the underside, flabbergasted, and realized that those vias drop down to a couple more caps on the underside! In addition to those, there are two other sets near the signal input jack and the input of the variable gain amplifier.

So I think I might still have found it, those caps on the underside might be the key difference. There may even be additional filtering on the input side of the variable gain amplifier too. My curve seems to lack that dramatic filter swoop, seems a little too linear. I don't know what the underside of the DS1102E looks like though, so I can't say for sure. All I know is that it seems like my scope is working fantastic with this mod, I wish I had another reference to compare to besides my unmodded channel. The DS1102C scopes at school are only 400 MS/s with no sinx/x feature, so they aren't good for comparison. Unfortunately all of our other 100 MHz scopes are analog and long separated from their last cal date.

Shine a light underneath the board and you will see everywhere that signal passes down. They cut out chunks of the inside layers around those areas.

flolic · « **Reply #179 on:** February 17, 2010, 10:52:23 am »

Ok, I modified both channels. I don't know if that was wise idea but it's over now

Few thoughts:
-First, original probe (for 1102E) is declared as 150MHz bandwidth and WILL attenuate higher freq. signals.
-Second, my modified scope (with homemade high bandwidth probe) easily picked up 446MHz PMR radio transmission from few meters away. It is easily seen on FFT display. Unmodified scope can show that transmission only if I put radio right next to the probe.

From that it is obvious that mod is working. But I am still worried about spurious/false readings...

flolic · « **Reply #180 on:** February 17, 2010, 10:58:45 am »

Quote from: rossmoffett on February 17, 2010, 10:25:15 am

I flipped to the underside, flabbergasted, and realized that those vias drop down to a couple more caps on the underside! In addition to those, there are two other sets near the signal input jack and the input of the variable gain amplifier.

Time to take it apart...
AGAIN!!!

rossmoffett · « **Reply #181 on:** February 17, 2010, 05:27:37 pm »

Quote from: flolic on February 17, 2010, 10:58:45 am

Quote from: rossmoffett on February 17, 2010, 10:25:15 am

I flipped to the underside, flabbergasted, and realized that those vias drop down to a couple more caps on the underside! In addition to those, there are two other sets near the signal input jack and the input of the variable gain amplifier.

Time to take it apart...
AGAIN!!!

I traced the two caps near the variable gain amplifier, they're coming off of the eight lead ADC driver chip. This is to be expected, they're in the datasheets for the ADC drivers, and there are two filtering the power on the ADC driver in the app note for the ADC.

The other filter is below the relay that doesn't appear on Dave's board, right by the input. I haven't traced it yet, I wonder if you could do in-circuit measurements of the cap and inductors so we can compare? The cap is huge for a SMT part, looks like a .1 uF. If you don't have an L meter, could you get the numbers maybe? My board is a couple of revision ahead of yours, but I can't tell that there is any difference.

I get 3.37 uF and 15.45 uF on the two little caps near the VGA.
194.2 pF on the cap underneath the relay and negative numbers on the inductor measurements.. guess the cheap-o LC meter can't handle this. They are both marked "580."

flolic · « **Reply #182 on:** February 17, 2010, 06:16:15 pm »

Big bottom cap is 210nF.
Two small components next to cap, marked ad 58D are 390k resistors.

Two small caps below VGA must be decoupling capacitors.
Sorry, nothing useful on the bottom side...

Maybe we should look for a components between ADC driver and ADC??

rossmoffett · « **Reply #183 on:** February 17, 2010, 06:48:45 pm »

Quote from: flolic on February 17, 2010, 06:16:15 pm

Sorry, nothing useful on the bottom side...

Not necessarily true, there are other bottom mount components under the ADC support circuit.

There's also an empty set of pads for an IC and three passive components near the bottom of the FPGA on mine. Did you take more pictures?

flolic · « **Reply #184 on:** February 17, 2010, 08:47:42 pm »

Bottom, not so good quality image:

rossmoffett · « **Reply #185 on:** February 18, 2010, 05:10:44 am »

Once I'm home and there's daylight I'll try hard to get a good shot of mine, there are significant differences on the bottom from that picture.. no potential filters though, I think.

flolic · « **Reply #186 on:** February 18, 2010, 10:42:36 am »

Quote from: rossmoffett on February 15, 2010, 10:10:49 am

OK, I think I have narrowed down what kind of chip the ADC driver is. I thought I saw an extra pad on one of Dave's close-ups, which would have explained why I couldn't find an 8-lead package, but upon close inspection from top views I can't see that it would be the case. Browsing the ADC drivers at the Analog Devices website seemed futile, until I checked a supplier. These chips are available in packages not described on the AD website. I noticed that the screen print around the part seems to be 3x3 mm. This leads me to believe they must have some oddball part, but the PCB still looks like it would fit these two parts, which come with the squared edges.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=AD8350ARMZ20-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=AD8132ARMZ-ND

They are 900 MHz and 350 MHz respectively. I'll have to crack it open again and take some measurements on gain and voltage to be sure which part it is, still could be any of the other 8 pin parts. The version with the worst (feasible) bandwidth is the AD8137, with a bandwidth of 110 MHz. The only lower ones clock at 38 and 30 MHz. I can find it in a package with bevelled edges in 3x3 mm, but not with the square ones.

and.. here's the AD8138 in the package that's in the scope:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=AD8138ARMZ-ND

A 320 MHz part.

No. I think that ADC driver chip is in a LLP-8 package.
Maybe one of these?
http://www.national.com/ds/LM/LMH6552.pdf
http://www.national.com/ds/LM/LMH6553.pdf

rossmoffett · « **Reply #187 on:** February 18, 2010, 01:45:23 pm »

Looks right to me, exact dimensions and all. Pinout seems to match.

mckee · « **Reply #188 on:** February 19, 2010, 01:04:27 pm »

Hello to everybody my name is Thomas and I am writing from Germany, I was reading the forum as guest , but discussion is so interesting that I will add something . It happened that I bought DS1022C few years ago, my original firmware was 1.03.02 , but I found on Chinese forum picture of this DSO with soft 03.07.01 so after digging the ne I found it as well with name
DS1000 firmware , I updated my DSO yesterday and it seems working well, I did not seen any major changes thou.
If somebody need this firmware please write to me or let me know where to drop the file , it is 1.2M zipped so no fit as attachment.
Forum in chinese but with some pics of inside
http://www.ourdev.cn/bbs/bbs_content.jsp?bbs_sn=3428440&bbs_page_no=1&search_mode=4&search_text=zxwr7282&bbs_id=9999
If you guys needs some help with chinese it is no problem to translate, I read chinese .

My question is how to upgrade and if its possible to 1022CD , is it only matter of the adding LH1116 Logic analyzer module or something more?
Thank you for understanding, if I missed this info in previous pages

Thanks for update.

rossmoffett · « **Reply #189 on:** February 19, 2010, 03:42:00 pm »

There is no "Logic Analyzer" module installed there.

The button to enable the logic analyzer is cut out, but the pad for the button is still on the PCB. If you slide the other buttons onto it and press, it will tell you that the module is not installed. I don't know what that means, or how to make it think it's installed, but the header for the logic analyzer is on the board.

rossmoffett · « **Reply #190 on:** February 21, 2010, 07:00:05 am »

Today I made two BNC cables and ran them in parallel to ch1 and ch2 from the sine wave generator. I tried to take measurements about every 1/2 MHz, but usually at least 1 MHz. The higher resolution gives some really interesting results!

For starters, I have to admit my test faults. I tried to keep three significant figures and a filled screen for precision, so every now and then I would adjust the attenuator on the sine wave generator. If you see both ch1 and ch2 moving, that's what's going on. It could also be because I switched ranges, or because the generator is generally unstable.

But.. look around the peaks. When my modded channel peaks, my unmodded channel drops, and vice-versa! What's going on here? Also, because I took the data to 150 MHz, you can see that there may be additional filtering going on somewhere.

Around 100 MHz, my modded channel starts dropping while the unmodded channel stays pretty constant. I think this should mean that I've succeeded, but what's going on before that?

Any ideas?

Dave, haven't heard from you in this thread for a while.

jahonen · « **Reply #191 on:** February 21, 2010, 07:26:33 am »

I suppose you didn't use any terminator at the scope end? Failure to do this will result reflections, which ruin your otherwise perfectly good data. Check also that the generator has 50 ohms output impedance. It looks like that you got the reflection peaks/valleys perfectly measured, just as the transmission line theory predicts, though.

For the record, when we measured my colleagues 100 MHz Rigol (using a VNA as a signal source) using that kind of terminated setup, we determined the -3 dB frequency to be about 170 MHz. Otherwise it was pretty flat.

Regards,
Janne

rossmoffett · « **Reply #192 on:** February 21, 2010, 08:05:20 am »

So THAT'S what those are for!

Thanks.

170 MHz stock?? That's amazing!

jahonen · « **Reply #193 on:** February 21, 2010, 09:05:12 am »

Yes, it was perfectly stock when we measured it. I think that it is quite normal to have shallow roll-off. For example, for my 300 MHz Agilent MSO6034A, the calibration measurement report says that at nominal 300 MHz, test pass limit is -3 dB and actual measured value is -0.8…-0.6 dB.

Regards,
Janne

rossmoffett · « **Reply #194 on:** March 05, 2010, 03:59:53 am »

I tried adding a 50 ohm resistance in my BNC cables and I still get that signal ghosting to some degree. Using my probes I don't get that effect, but I feel like I can't really be sure about this hack until I can compare it to a quality scope. I guess I'll have to borrow one with some commercially made BNC cables, but I still only have access to a 100 MHz unit.

macpod · « **Reply #195 on:** March 05, 2010, 04:36:16 pm »

I noticed the DS1052E has an option MemDepth which lets you set the device to Normal (16K/8K) or Long Mem (1M/512K).

I could understand having this setting so you could save more waveforms on the device, but is there another benefit to having this setting that I am overlooking?

Brett · « **Reply #196 on:** March 06, 2010, 10:46:50 pm »

I just bought 3 Rigol DS1052E's in addition to the one I already have. Some of you have purchased yours through my seller as well, and my boss is getting one now too. Of the three, one was for my buddy and two were for work. Everyone loves them. These are the perfect little scopes for the lab and travel.

One bug I found recently is if you try to save a file with an underscore before it '_', it locks up the firmware. Power cycling restores it, but beware!

BTW: The price I got on the 3 scope bundle was $407 each shipped. Single scopes are regularly going out as $420 shipped. I also had no problems with US Customs on the larger 3 scope package.

Enjoy these pictures:

Brett · « **Reply #197 on:** March 08, 2010, 05:11:26 am »

Quote from: macpod on March 05, 2010, 04:36:16 pm

I noticed the DS1052E has an option MemDepth which lets you set the device to Normal (16K/8K) or Long Mem (1M/512K).

I could understand having this setting so you could save more waveforms on the device, but is there another benefit to having this setting that I am overlooking?

The real benefit is that if you REALLY need to over sample at a relatively slow timebase (10s or 100s of milliseconds), you can with the Long Mem. The downside to Long Mem, is that if you try to save it to USB drive, it takes quite a while to do so. WHen I first used it, I thought the scope had locked up. Later I learned to take 5-10 minute breaks after pressing the save button, as it creates a >20MB CSV file.

If you are saving some analog waveform, and there are not a lot of fast transitions... setting the memory depth to Normal is plenty sufficient.

If you are on the other hand trying to capture 5 minutes worth of I²C or SPI data, then by all means turn on the Long Mem. Analyzing and graphing 800K+ points of data is another problem you will have, but it's there if you need it.

The Normal mode is going to be your bet bet overall, and for analog waveforms I wouldn't even bother with the CSV output. Just save as BMP and make sure you have the waveform positioned by of a pair of major grid axis to be able to gauge amplitude and duration accurately. I thought the CSV with analog waveforms would help me create some more detailed EXCEL graphs. Well Excel only graphs 32000 points at a time, and because there is not a lot of precision in the A/D samples, you end up with a lot of the same numbers in your graph, and the end result is a nice stair-stepped waveform (instead of a smooth line). There is probably a way to filter the data better to integrate and smooth things out, but I've yet to work on that one.

joelby · « **Reply #198 on:** March 08, 2010, 11:47:26 am »

Try saving it as a WFM file. It is a binary format, so it is much more compact and much quicker to save to flash than CSV.

Apparently the software that comes with the scope might process them, but I haven't bothered. Just use the Matlab script to do it: http://www.mathworks.com.au/matlabcentral/fileexchange/18999-read-binary-rigol-waveforms . It will probably also work in the free Matlab-alike, Octave, or you could examine the code and write a WFM to CSV conversion tool pretty easily. Something like gnuplot will probably have more success than Excel with plotting many points.

Brett · « **Reply #199 on:** March 09, 2010, 06:47:08 pm »

Cool, thanks Joel!

EDIT: As an alternative, if you don't want to download Octave and get it all set up, here is a little utility based on the readRigolWaveform.m function to decode WMF files:
http://qt.tn.tudelft.nl/~gsteele/rigol2dat/


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Author Topic: The Rigol DS1052E (Read 644982 times)

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