The Rigol DS1052E

[charliex]

The courts have generally sided with the OEM's on grey imports, there are some laws that offer protection for the OEM.

But they can make effectively their own law, since its simply contractual with their distributors/dealers.

[rossmoffett]

We have the 100Mhz Rigol models at school.  Knobs fell off of two of them and they were sent back to the dealer for repair, they came back with a USB stick containing a firmware upgrade.  I don't recall the exact steps, but the front USB port is compatible with USB flash drives.  I just plugged it in and selected the file somewhere, I think.

Wonder what would happen if you were to use the 100Mhz model firmware in a 50Mhz machine?

[rossv]

I'm officially pissed off now.

I've just tried to order a rigol DS1204B in the US and was told by the shop owner that rigol has officially forbidden them to ship to germany! WTF !?!

European shops are way too expensive. I don't feel like paying a penalty fee just because I don't happen to live somewhere else. There's a price difference of about 450$, and that's _after_ paying import tax. Seems like I will have to look for a different brand.

Have you tried DealExtreme? I bought from them and had no problems. You should use a credit card for safety and make sure you select most expensive/secure shipping option. You probably already know, but in Germany you will be forced to pay extra Zoll for something of that value :-(.

http://www.dealextreme.com/details.dx/sku.30573

Ross..

[madworm]

Yes, I know about import tax and such. Still it would've been a steal. The DS1204B is sold for 1850€ (about 2600$ US) in Germany. I just don't feel like subsidizing Rigol sales elsewhere by paying  'a little extra' for the scope here.

The DS1052E costs about 830$ US in Germany.

[rossmoffett]

I couldn't take it anymore.. bought one. 

I'd love to have the 100Mhz model that I've used at school, but really all of my analog development is limited to well under a Mhz anyway.

[pisarm]

Madworm - the DS1052E can be had for ~625$ in Germany (including free shipping) from
http://www.progshop.com/shop/oscilloscopes/Rigol-DS1052E.html

I bought a DS1102E from them a few months ago which I am very satisfied with.

[rossv]

Yes, I know about import tax and such. Still it would've been a steal. The DS1204B is sold for 1850€ (about 2600$ US) in Germany. I just don't feel like subsidizing Rigol sales elsewhere by paying  'a little extra' for the scope here.

The DS1052E costs about 830$ US in Germany.

It is also expensive in Australia and much of the world, so why don't you but it from DealExtreme (and use credit card for safety)?

[madworm]

Well, because I really don't want the 50MHz one, but the 4CH 200MHz scope ;-)

And that one costs 1850€ in Germany (including tax and other crap). If I could import that one from the US, I'd end up with just 1600€ including tax and shipping. So apparently someone is trying to suck 200€ out of my pocket. I don't know if it's Rigol or all of the dealers in between, but I don't like it. Don't get me wrong, but why should I have to pay more than people living in the US?

[rossmoffett]

Well, because I really don't want the 50MHz one, but the 4CH 200MHz scope ;-)

http://www.alibaba.com/trade/search?SearchText=rigol&Country=&CatId=50502&IndexArea=product_en&ssk=y&sq=y

Mail a few sellers there and see what you can get.

[madworm]

Hmmm.

I've got in contact with my local Lecroy representative. I'll have to see what they can tell me about the WaveAce224 first. Although they currently have a promotion going it will certainly cost a lot more, but Rigol have really pissed me off. I'm quite unforgiving with respect to being treated like an idiot. And the service should be much better as well.

[frederir]

Doing some research on DSO, and found this thread. From the photo we can say there is a least one other component overclocked, the FIFO.
Reference is IS61LPS25636A-200 (http://www.issi.com/pdf/61LPS25632TD.pdf), It is either 32 ou 36 bits wide and can run at a maximum of 200MHz. Now you have 1G sample per second, assuming 8bits, if you want to store it in a 32bits RAM you need to run at 250MHz. Then you are 50MHz over limit....
The other possibility is to reduce samples from 8bits to 6 bits and use the 36bits to store 6 words of 6bits at each clock, you can the store 1.2G samples per second but only with 6bits resolution.
Last solution you can store 4.5 samples of 8 bits each clock in 36bits but it would get you only 0.9G samples per second and the software would be a bit more complex.
My guess is they run the fifo in 32bits and overclock it at 250MHz. Can someone put a frequency counter on the pin 89 of the ISSI chip ?

F.

[rossmoffett]

Can't wait until mine arrives so I can get a look inside.

I took another look at the 100 Mhz Rigol scopes we have at school and they are the 1102C model.  400 Ms/s!  Probably the same 100 MHz analog board with different clocks/firmware on the digital side, before they figured out they could reliably overclock.  Would it be useful to graph its frequency response curve?

[bushing]

they are very similar, but there's differences in the pcb for sure. The 1052 looks like it's using a Cosmo KAQY214S SSR ( http://www.cosmo-ic.com/object/products/KAQY214S.pdf) instead of the mechanical relay of the 1102. Could this limit the bandwidth?

other than the components ralated to the SSR everything else seems the same to me?

The board in my DS1052E is exactly like FLolic's-- down to the FT relays and silk-screened labels. The only difference is the minor 'patch' on the LCD driver IC on mine. I believe Dave has a slightly earlier rev board.  

I would suspect the 'shaved' IC's in the analog section-- there's has to be a reason why they insist on defacing the labels.

I just got my DS1052E in the mail (thanks to Brett for the tip!) -- is this where the 50MHz/100MHz investigation ended, or did anyone make further progress?

[rossmoffett]

My scope is about like Dave's in build quality, looks very nice except for some similar mess that others have observed due to the rubbed off A/D converters.

Has anyone been probing around in there lately?  I have mine apart already and I'm looking at the Analog section.  While the 50 MHz and 100 MHz models have what seems to be an identical front-end, I have a theory.  Mind this comment from the teardown blog comments:

Mastro Gippo October 13th, 2009 at 02:43

Mh.. The scratched 16 pin IC in the analog part should be an AD8370
http://www.analog.com/en/amplifiers-and-comparators/variable-gain-amplifiers/ad8370/products/product.html
but I don’t know why they are scratching it! There’s nothing to be ashamed of, it’s a 750MHz part…

Rigol makes some 300 MHz scopes too.  What if the analog front end on the 100 MHz scope is bandwidth limited also, and we've got filters on both models with different values?  What if our *real* bandwidth can be even higher than 100 MHz?

I've found something that I need to investigate with a better scope, will post details if it ends up being anything of significance.

[rossmoffett]

I just threw caution to the wind and made the mod..  I'll do a write-up ASAP tonight, I've been up all night playing with it and I've got to go to a robot build meeting.  After you find out what I've done and why you can better decide whether it was a good idea or not.  I don't want to say what I did until I can thoroughly explain it.

Channel 1 (yellow) is unmodified, Channel two (blue) has the mod.  It seems to correct the curve that is shown in the other Rigol post (blog specific forum).  I don't know what happens around 100 MHz, honestly.  The function generator I'm using is a piece of trash and very unstable, 100MHz is where the road ends.  I was only able to get curves this good by using time averaging, you can tell that the VPP stability is crap, but since both channels are referencing it, the data should still be good for proportional reference.  Stability of the function generator around 80-90 MHz was too horrible to even post.

20MHz
30MHz
40MHz

V1 = .7(V2)
50MHz
60MHz
70MHz
100Mhz

EDIT:
My high frequency signals are fine, I shouldn't have taken measurements before closing the shielding back up again.  I just compared the scope with a Rigol DS1102C (100 MHz, 400 MS/s) and that scope has a hard time keeping up!  The modified channels signal is clean and consistently much stronger than the 50 MHz channel.

[EEVblog]

This looks super exciting Ross, you may have cracked it!
Please detail your mod as soon as you are able.
Also, what does it look like with a square wave and a normal clip probe? The overshoot and undershoot is an easy way to see how the high frequency response has improved.

Dave.

[EEVblog]

Rigol makes some 300 MHz scopes too.  What if the analog front end on the 100 MHz scope is bandwidth limited also, and we've got filters on both models with different values?  What if our *real* bandwidth can be even higher than 100 MHz?

Phil Allison has measured the usable bandwidth here:
http://groups.google.com.au/group/aus.electronics/browse_frm/thread/8db8df6c7f9f710/6edf366688b538db?lnk=gst&q=rigol+phil#6edf366688b538db
400MHz for a visible and viewable waveform!
So there could certainly be much more to this front end than meets the eye.

Dave.

[xani]

If that was true, Rigol scope is probably best deal in history, 200Mhz (assumming 5 probes per cycle) for $400, insane...

[rossmoffett]

I wonder if I could have permission to use someone's photographs of the analog input section?  My digital camera got smashed up the last time I flew and I haven't replaced the LCD yet.

I checked out a function generator from school, I wish I had checked out some 100 MHz scope probes too!  It turns out that this is crucial too.. I should have known, the 50 MHz probes that come with it have their dB plots in the documentation.

EDIT:  FLAWED MEASUREMENT
Here is what a 1 MHz square wave looks like.  There are 150 MHz transients in channel two that don't show up in channel one.

[EEVblog]

Feel free to use my internal pics.
When testing with a signal generator it's best to use a good coax instead of the probe.

Dave.

[rossmoffett]

Dave, I know I'm supposed to use BNC connectors, it's just that I don't have them.  This is actually my first oscilloscope so I just have the out-of-box parts and whatever I can check out from school.

I'll do a full how-to when this is peer reviewed, I think, but here's what I found.

At first I thought it would be trivial, it was pretty clear that this was a Butterworth filter from the frequency vs. voltage plots that have been posted, so there should be some row of inductors and capacitors.  I found one, but it was a filter for the AD8370 power.  I figured that out by tracing it to the pin and then checking the datasheet.  Then as I read the datasheet (should have thought of this FIRST) I ran into something interesting.  In the app notes they specifically mention using this as a variable gain amplifier for low-resolution AD converters.. like an 8 bit AD converter.  This is on page 19 of 28, and right at the top of the page is a Butterworth filter with a Cauer topology.  This is in case the AD converter can't handle high frequencies.. or in case you want to use the same design for two differently priced oscilloscopes.   NO WONDER the part is rubbed out!

VHI is pin 8 and VLO is pin 9, this is the amplified output signal. There are two gold pads on the PCB that are labelled as test points on the DS1102E.  I noticed attenuation here.  Then, looking through the comments on Dave's teardown blog I saw that someone guessed the part number for the smaller, 8-pin part.  It wasn't the right part number, but it fit the bill exactly (this is not an Analog Devices part, though, because it matches none of their ADC drivers, not a TI part either).  The only thing that was off was that the VHI and VLO pins were reversed, so I just assume this is the AD converter buffer.  The datasheet reference circuit for the AD9288-40 ADC uses an AD8138.  This doesn't come in a TSSOP-8 package.  In fact, I can't find any op-amp with that configuration in a TSSOP-8 from Analog Devices.

Looking at the board, I noticed that the signal split in two directions at the test point.  One way went to the buffer and the other went through a capacitor..





Re-organize a bit, and it's clear that there is a high-pass filter straight between signal HI and signal LO.  This is why some of my measurements were out of phase, even though both channels were measuring the same signal.
(values based on in-circuit measurements by a cheap LC meter, not in stone)



The via hanging off of the inductor has a direct path to the shift register, I'm not sure why.  It's not grounded, and I don't know why it would be tied to a logic high anywhere, not sure what's going on.  There's a via hanging off of the inductor at the top too, I couldn't find where it goes.

So my "hack" was just to remove the capacitor on the VoutHI pin.  I just now took all of the measurements as I was making the drawings, and I took out the other cap on the VoutLO pin.  There doesn't seem to be any additional change, I believe that the AD8370 output is isolated from ground, which means when you sever just one capacitor the whole filter is rendered ineffective.  So all that has to be done is cut the path to the filter somehow.  I removed a capacitor with my soldering iron, you could also just slice the trace (but that's a little dirty).

In closing, your mileage may vary, at your own risk, warranty void and null, etc etc.

Here are some more good pictures, showing how the FFT smooths out with a mod and how a square wave shapes up.  Flip between them quickly and the difference is very noticeable.  Again, channel 1 (yellow) is unmodified, channel 2 (blue) has the filter removed.

[rossmoffett]

If anyone else is willing to try this, I suggest you just pop up one end of the capacitor on pin 8 of the variable gain amplifier (the one right below the topmost round golden test pad).  This will allow you to easily undo the mod later if you wish, and if you're a skilled SMD solder wiz.

I'd love to see what the results are with better lab equipment, is anyone gonna give it a go?

[rossmoffett]

I did the best I could, used a "BNC to alligator clips" cable and split the output from my high frequency function generator to both channels with short wires.  The stability and accuracy appears MUCH better than when I was using probes, so I charted the unmodified output vs. the modified output.  The voltage gain in the modified channel is very apparent.

I used equivalent time sampling with normal acquisition until I was down to about 10 MHz, then the generator was too unstable and I had to time-average it.

Comparing it to luky315's measured frequency response, it looks like I have over 100 MHz bandwidth now!

[rossmoffett]

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.

[flolic]

I'd love to see what the results are with better lab equipment, is anyone gonna give it a go?

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...