REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol

[Carrington]

Great 
  Marmad, you know if someone has tried to establish a BW of 300MHz by SPI command?
  And this BW was verified?
Thanks

[Wim13]

Great 
  Marmad, you know if someone has tried to establish a BW of 300MHz by SPI command?
  And this BW was verified?
Thanks

If you look at the datsheet, you must see that for the 233 Mhz bandwidth of the 2202,
the 350 Mhz options is already used. The datasheet is showing a diagram measured on
the best possible situation. I dont think you can get more out of it.
The 200 Mhz line is to narrow for the 2202.

Also because the entry of the DS 2000 is made for 1 Mohm

[Carrington]

Perhaps, and -3dB @ 233MHz is due to the combination of LMH6518 @ 350MHz and the response of the stages before the LMH6518.
In such case would interesting change the MMBFJ309, N-Chanel RF Amplifier, by another similar with better frequency response.
We only need sniff the SPI of the LMH6518 to check it. Has anyone done that yet?

[tinhead]

Perhaps, and -3dB @ 233MHz is due to the combination of LMH6518 @ 350MHz and the response of the stages before the LMH6518.
In such case would interesting change the MMBFJ309, N-Chanel RF Amplifier, by another similar with better frequency response.
We only need sniff the SPI of the LMH6518 to check it. Has anyone done that yet?

for what? when you wish to imporve something, draw first the schmatic of the inpustage, then do some simulations and THEN (and only then) check if something can be improved. Simply "replacing" something by what so ever wonder part will not imporve anything but probably make the whole frequency response worse.

[Carrington]

Hi tinhead!

I've also thought draw the schematic, but I do not know when I can do it.
And only with a picture (that is the only that I have for now) is complicated.

I think there are similarities with this:
http://elinux.org/images/c/c6/Das_oszi_schematic.pdf
See Q01_1 at page 2, and other small changes to get 200MHz of BW.

[IanJ]

Hi all,

Is this a bug.....or is it just me intepreting the scope wrongly.?

DS2072 (FW v.01.00.00.03)

- Turn on both channels, probe a couple of different DC voltages.

- Whilst Ch.1 selected go to Vertical menu and select Vavg (yellow). Ch.1 Vavg is now displayed at bottom of screen in yellow.

- Select Ch.2 and go to Vertical menu and select Vavg (blue). Ch.2 is now displayed at bottom of screen in blue.......however, Ch.1 which is still yellow now reads same voltage as Ch.2.

I was looking to have Ch.1 & Ch.2 Vavg at bottom of screen. Whatever I do both the Vavg's at the bottom of the screen always read the same voltage.

PS. If use the DISPLAY ALL function under MEASURE both the V.avg's are displayed correctly in the pop-up.

Ian.

[Wim13]

Hi all,

Is this a bug.....or is it just me intepreting the scope wrongly.?

DS2072 (FW v.01.00.00.03)

- Turn on both channels, probe a couple of different DC voltages.

- Whilst Ch.1 selected go to Vertical menu and select Vavg (yellow). Ch.1 Vavg is now displayed at bottom of screen in yellow.

- Select Ch.2 and go to Vertical menu and select Vavg (blue). Ch.2 is now displayed at bottom of screen in blue.......however, Ch.1 which is still yellow now reads same voltage as Ch.2.

I was looking to have Ch.1 & Ch.2 Vavg at bottom of screen. Whatever I do both the Vavg's at the bottom of the screen always read the same voltage.

PS. If use the DISPLAY ALL function under MEASURE both the V.avg's are displayed correctly in the pop-up.

Ian.

Read the first post of this thread, all the bugs are listed....

And yes it was a bug, solved in the latest FW, you can download on the first page.

[IanJ]

Read the first post of this thread, all the bugs are listed....

And yes it was a bug, solved in the latest FW, you can download on the first page.

I did.....must have missed it.

Cheers.

[tinhead]

I think there are similarities with this:
...
See Q01_1 at page 2, and other small changes to get 200MHz of BW.

hehe, i know that schematic, i have drawn it.

Yes, they are similar, J-FET/NPN (MMBFJ309 / MMBTH10LT1) and two BC846B + AD8510.
However there is second MMBTH10LT1 in DS2000 series, as well the attenuator/compensation circuit is new.

[Carrington]

Yep!

Of course, and resistors unmarked too.
Someone has a broken DS 2000  ? Donate it to us please, we need one LOL.

PS: By the way very good job with the schematic tinhead.

[Marc M.]

Good news everyone.  I received my DS-2072 from TEquipment today  . 

The revisions as received were:
     Serial: DS2A151200xxx (under 500)
Soft Ver.: 00.00.01.00.05
Hard Ver.: 1.0.1.0.0
        SPU: 03.01.02
       WPU: 00.06.00
        CCU: 12.29.00
        MPU: 00.05

After doing some bandwidth and risetime tests, I tried to apply the keys to unlock bandwidth and options.  I got all the options turned on except for 200Mhz b/w.  The model # stayed 2072  . I tried several times, first just the DSA9 key, then the DSAR followed by DSA9 keys but it still stayed a 2072  .  I tried updating the firmware to 01.01.00.02 then applied the DSAR & DSA9 keys.  Success!  This time everything including the 200 MHz b/w were unlocked  . Not sure why it wouldn't work prior to the FW update

Using a Rohde & Schwarz SMS generator into a 50 ohm passthru, I did 2 simple plots of freq. vs mV thru 500 MHz before and after applying the keys.  The results tracked close to Wim13's results with a similar setup (post #1215 Pg. 82).

To check risetime, I used a Tek PG 502 pulse generator with a spec'd risetime of <= 1 nS feeding the DS2072 thru a Tek 50 ohm feedthru terminator.  Prior to applying the keys, I got a risetime of 2.5 nS.  After applying the keys, it dropped to 1.3 nS, also in line with other folks results IIRC.

Again, a huge thank you to Marmad, cybernet, teneyes, Wim13, and all the others that have contributed so much to the collective knowledge regarding these scopes .

Marc -

   

[Marc M.]

...we could get without much difficulty A BW of 300/400MHz...

Whatfor? The scope has not been calibrated for this. Maybe a 70Mhz scope was only calibrated for 70 Mhz so even 100 or 200Mhz measurements are not valid...

Nonsense!  The hardware and firmware are identical between the 2072, 2102, and 2202 models.  The only difference between models is the entry of a key(s).  Many folks here have done exhaustive testing prior to and after applying these keys and have proven this to be fact.  I just received my 2072 today and have done some basic tests for myself all of which have tracked the others work just about perfectly.  If you go thru the couple of threads regarding the 2072, you can see some excellent plots done by Wim13 showing the vertical bandwidth past 400 MHz. 

One of the tests I performed that I haven't seen elsewhere was a test of the horizontal timebase accuracy.  Using a Tektronix TG-501 (checked against my Rubidium standard - spot on), I checked my 2072 horizontal timebase at several sweep speeds.  The max sweep frequency of the 2072 is 5 nS so we can assume it would be calibrated at that setting.  After applying the keys, the 2 nS speed is unlocked, so that would be questionable as to it's accuracy.  Here are 3 screenshots of the TG-501 feeding the unlocked DS2072 at 10,5, and 2 nS:




As you can see, all were pretty much spot on.  So any questions regarding the reduced accuracy of a unlocked DS-2072 vs a DS-2202 are baseless. 

[ve7xen]

Has anyone else tried using the 'advanced' math functions and found them... strange? I was fooling around tonight and thought the integrate function wasn't doing what I wanted, so I fed in a pure sine wave into Intg(CH1) and got... oddness. It's vaguely sinusoidal, but with a changing offset and very small amplitude. The slant of it changes slowly with time as well, moving around randomly despite a stable trigger and clean input signal. Anyone know what's going on here - I'd expect a simple phase shift?

The Diff(CH1) is even weirder, in almost the opposite way. This one goes up to GU on the units and also looks like crap.

Are these functions intentionally not performing the Integral and Derivative functions I learned in calculus?

FWIW I'm running the latest firmware whatever .02.

[jonese]

...we could get without much difficulty A BW of 300/400MHz...

Whatfor? The scope has not been calibrated for this. Maybe a 70Mhz scope was only calibrated for 70 Mhz so even 100 or 200Mhz measurements are not valid...

Nonsense!  The hardware and firmware are identical between the 2072, 2102, and 2202 models.  The only difference between models is the entry of a key(s).  Many folks here have done exhaustive testing prior to and after applying these keys and have proven this to be fact.  I just received my 2072 today and have done some basic tests for myself all of which have tracked the others work just about perfectly.  If you go thru the couple of threads regarding the 2072, you can see some excellent plots done by Wim13 showing the vertical bandwidth past 400 MHz. 

....

I think it's a bit too early to state that.  We have no knowledge that Rigol has calibrated a 2072 for anything higher than 70 MHz (we don't know what their process is in production).  Just because you can see stuff visually up to the -3db drop, doesn't mean it's accurate.

Perhaps if we had a dump of the calibration data table would shed some light on what parameters could be calibrated and if there are some parameters that only the 100/200 scopes would utilize.

[ve7xen]

I think it's a bit too early to state that.  We have no knowledge that Rigol has calibrated a 2072 for anything higher than 70 MHz (we don't know what their process is in production).  Just because you can see stuff visually up to the -3db drop, doesn't mean it's accurate.

If you're talking calibration constants, that's not a hardware difference...

If someone has measured a DS2072->DS2202 at reasonable intervals up to -3dB with an expected and linear curve, I think it is data enough to know it's not going to be meaningfully (way) out. Strictly yeah, you shouldn't trust it, but all signs point to the data being good anyway, and after all the experimenting done around here I'm fairly confident the frontends are identical. There may be additional calibration at the factory, but like buying used gear on eBay, it's more than good enough for almost any use you're going to encounter with a scope you hacked.

I wonder if the self-cal routine would null out any nonlinearities, if any did appear on these scopes.

[poida_pie]

re: anti-aliasing having no effect.

I beg to differ. Try the FFT function, with and without AA.
It seems to limit something or other.
The attached images show a 1 MHz square wave, 1v p/p, on an unmodified DS2072. Signal from a Rigol DG1022, via 50 ohm termination.
Blackman windowing selected for the FFT.

Note how the FFT horizontal scale changes.
When AA off, lots of garbage about the main tones, and how when AA is on, the spectrum looks about right.

 

[Teneyes]

To help show the bandwidth
Below are 2 displays for a 4-40 MHZ frequency Sweep (exp)
  1st display is Capture of multiple frames in 3D format
  2nd display is same as above but with the BW Limit set to 20 MHz
  3rd display is Animation of every 200th frame  with the BW Limit set to 20 MHz

Notes:
    the 1st frame is with 2 cycles on display, so scan was fine adjusted to 36nsec/div
    the DS2072 set to show -0.8 to +0.8 Vdc
    the RUU program shows  -1.0 to +1.0 Vdc

My Generator only goes to 60MHz so , I am asking if somone with 500 MHz Generator could repeat this test to show higher frenquencies and maybe with the 100 MHz filter

[marmad]

re: anti-aliasing having no effect.

I beg to differ. Try the FFT function, with and without AA.
It seems to limit something or other.

Great! It's good to know that it 'limits something or other'.    Seriously, this has been discussed ad nauseum - so, for hopefully the last time: anti-aliasing has (virtually) no effect on aliasing (as defined for a DSO) - which, judging by it's name, you might reasonably expect it to, you know, prevent. 

How to do it? It's not rocket science - over-sample, then randomly decimate for the 'required' sample speed = stochastic sampling. Done.

[darrylp]

Have noticed from videos of people ds2xx2 that all earlier shipments come with switchable x1 x10 probes. Some people mention 350MHz bandwidth. Well my scope came with x10 non selectable , rigol info sheet says 300MHz bandwidth. Now I've got other probes for accessing the 500uV setting, but who else has the x10 only probes ?


--
 Darryl

[jsykes]

Have noticed from videos of people ds2xx2 that all earlier shipments come with switchable x1 x10 probes. Some people mention 350MHz bandwidth. Well my scope came with x10 non selectable , rigol info sheet says 300MHz bandwidth. Now I've got other probes for accessing the 500uV setting, but who else has the x10 only probes ?


--
 Darryl

 
My 2202 came with the x1-x10 switchable 350MHz probe model RP3300. What is the model # of yours?

[marmad]

Have noticed from videos of people ds2xx2 that all earlier shipments come with switchable x1 x10 probes. Some people mention 350MHz bandwidth. Well my scope came with x10 non selectable , rigol info sheet says 300MHz bandwidth. Now I've got other probes for accessing the 500uV setting, but who else has the x10 only probes ?

The RP3300 x1/x10 switchable probes have been the standard included probes for the DS2000 series since they first started selling them. Where did you buy your DSO?

This is from the DS2000 User Manual:

[Xyphro]

Hi!

I found a new bug while programming this here: http://www.xyphro.de/blog/index.php?entry=entry130705-223439

The DS2072 does not accept an INITIATE_CLEAR class command over the USB interface. This command is a required command according to the USBTMC specification. The Scope does not react at all to it, and the USB transfer times out.

Other USBTMC instruments like DS1052, Siglent SDG1020 respond well to this command.

Another thing I noticed - maybe already known and not a bug.
In 500uV/DIV mode, the scope is internally set to 1mV/DIV and the data scaled by a factor of 2. This can be noticed when reading out the waveform data. The LSB is always 0. This effectively reduces the ADC resolution by 1 bit / dynamic range.

Best regards,

Kai

[alank2]

I tried several times, first just the DSA9 key, then the DSAR followed by DSA9 keys but it still stayed a 2072

Is there a purpose in loading the DSAR first, then DSA9 second?

[marmad]

Another thing I noticed - maybe already known and not a bug.
In 500uV/DIV mode, the scope is internally set to 1mV/DIV and the data scaled by a factor of 2. This can be noticed when reading out the waveform data. The LSB is always 0. This effectively reduces the ADC resolution by 1 bit / dynamic range.

The 500uV setting is NOT a scaled setting (manufacturers list this in the specs if it is - such as the Agilent X-Series) - but I'm not sure why the LSB is always 0 when you look at the display memory. In any case, it's not important - since it only has to do with the DSO screen - and the sample memory contains the real data, including the LSB.

[Xyphro]

Are you sure?
I can also clearly see on the screen, that the signal is scaled. The steps are clearly visible and larger as compared to e.g. 1mV/DIV.