Sniffing the Rigol's internal I2C bus

[Strada916]

Many thanks to the people that made this happen. Learning all the time. DS1074ZS to DS1104ZS.

[linux-works]

yes, the model # changes but this does NOT make the scope work any faster.  the bw is still the same, from what I've seen.

I know my sig gen is flat to 250mhz and so doing a test at the 100mhz level is pretty trustworthy.  I just did not see any diff in cutoff from before and after the upgrade.  model # did change, no argument there, but it was a 70mhz scope before and its still a 70mhz scope, now.

[Strada916]

yes, the model # changes but this does NOT make the scope work any faster.  the bw is still the same, from what I've seen.

I know my sig gen is flat to 250mhz and so doing a test at the 100mhz level is pretty trustworthy.  I just did not see any diff in cutoff from before and after the upgrade.  model # did change, no argument there, but it was a 70mhz scope before and its still a 70mhz scope, now.

Thanks. I was more after the other options anyways. But thanks

[linux-works]

same here.  I bought the 4ch scope for its proto decode, storage and views.  70 to 100mhz means nothing, especially since I was able to see waveforms at 250mhz very easily.

[Orange]

I have an original DS1104Z, and the B/W is about 125MHz (-3dB). The build in hardware counter works OK till 110Mhz, if you go higher it gives unreliable results.

Perhaps RIGOL has done some other limiting to prevent B/W upgrades on the 70MHz model.....

I still think this is an amazing piece of test gear for the money....especially if you add the triggers, decoding and memory options

[linux-works]

I did notice the built in counter stopped being reliable at 100mhz or just a bit above that, maybe 110.  it certainly did not count much above that range.

the waves did show up (I did not have square or triable, only sine) well beyond the 100mhz point.

and again, I was not talking about the 3db point, I was referring to a visual drop-off as you slowly bring the freq up and watch for vertical deflection changes.  this will be well below the '3db point' but I wanted to see where any falloff starts to happen.  it was the same point on the pre-mod and post-mod scope.

I'll see if 125mhz ends up being about 3db down.  it may very well be; but if so, then it probably was that way before the mod, as well.

[marmad]

I did notice the built in counter stopped being reliable at 100mhz or just a bit above that, maybe 110.  it certainly did not count much above that range.

the waves did show up (I did not have square or triable, only sine) well beyond the 100mhz point.

and again, I was not talking about the 3db point, I was referring to a visual drop-off as you slowly bring the freq up and watch for vertical deflection changes.  this will be well below the '3db point' but I wanted to see where any falloff starts to happen.  it was the same point on the pre-mod and post-mod scope.

I'll see if 125mhz ends up being about 3db down.  it may very well be; but if so, then it probably was that way before the mod, as well.

As mentioned many times before in regards to the DS2000 series (and is likely applicable to DS1000Z series as well - unless it's not using the same LMH6518 gain amp), there very well could be ZERO difference between the 70 and 100MHz models (aside from the model number, marketing, and price). There is no 70MHz BW cutoff possible with the LMH6518 chip - only 20, 100, 200, etc...

[linux-works]

200+ pages of topic, sorry, can't keep up

are you saying that a stock, out of the box 70mhz scope and the 100mhz version are going to test the same at the falloff point and/or 3db points?

(1000z series; I don't have the 2000 and that's a totally different scope anyway).

[marmad]

are you saying that a stock, out of the box 70mhz scope and the 100mhz version are going to test the same at the falloff point and/or 3db points?

(1000z series; I don't have the 2000 and that's a totally different scope anyway).

That's my guess, based on what Rigol did with the DS2000. But I don't have one, so I can't test it.

[Wim13]

I have an original DS1104Z, and the B/W is about 125MHz (-3dB). The build in hardware counter works OK till 110Mhz, if you go higher it gives unreliable results.

Perhaps RIGOL has done some other limiting to prevent B/W upgrades on the 70MHz model.....

I still think this is an amazing piece of test gear for the money....especially if you add the triggers, decoding and memory options

I measured an upgraded 1074 ( with Marconi sig.gen. 2019a, level -20 dBm)

 10 Mhz  0 db
 70 Mhz -1.1
 80 Mhz -1.5
 90 Mhz -1.7
100 Mhz -2.0
110 Mhz -2.4
120 Mhz -2.7 counter still working
130 Mhz -3.0 counter not working
160 Mhz -4.0
200 Mhz -5.4

300 Mhz -10 dB
400 Mhz -16 dB

So thats well within specs for a 100 Mhz DSO. no complains.
And seems to be the same as Orange measured on his 1104

[linux-works]

did you do the same test before the upgrade?

can the scope be reverted and then put back again, for a/b testing?

I should have done measurements before I did the upgrade.  damn.  sorry, just didn't think it would be new info so I only visually looked at things before and after rather than writing down actual 3db levels.

[Wim13]

Yes , you can uninstall the options, ( via SCPI) and

No , i dont have measured data before upgrade, will see next week if i can get any.

The counter has an other bug, put the DS1000 on AC trigger, and the counter wont work after >50 Mhz..!?

[seronday]

The Frequency Response plot for un-modified DS1074Z is here.
https://www.eevblog.com/forum/testgear/rigol-ds1074z-inside-picture/msg337710/#msg337710

[Wim13]

The Frequency Response plot for un-modified DS1074Z is here.
https://www.eevblog.com/forum/testgear/rigol-ds1074z-inside-picture/msg337710/#msg337710

That makes the 1104,  + 1 dB better over the whole range.
It is good to see that this + 1 dB is on all measured points for the 1104 compared to the chart mentioned.

[mrflibble]

That makes the 1104,  + 1 dB better over the whole range.
It is good to see that this + 1 dB is on all measured points for the 1104 compared to the chart mentioned.

Indeed. Same difference on all points makes it much easier to root out systematic error.

[Orange]

DS1074Z = 90 MHz
DS1104Z = 125MHz

So that means that the myth around the '70MHz / 100MHz scopes are a marketing thing' is busted for the DS1000Z series.

I can tell you also that the DS2000 70 MHz and 100MHz scopes are different, I know this from my own measurements, I have both.

[marmad]

I can tell you also that the DS2000 70 MHz and 100MHz scopes are different, I know this from my own measurements, I have both.

The 'idea' that the 70MHz DS2000 can do up to at least 100MHz <= 3dB is based on a number of other owners' measurements that were actually posted on this blog.

[Orange]

I can tell you also that the DS2000 70 MHz and 100MHz scopes are different, I know this from my own measurements, I have both.

The 'idea' that the 70MHz DS2000 can do up to at least 100MHz <= 3dB is based on a number of other owners' measurements that were actually posted on this blog.

Yes for sure I agree with you, but the suspicion that a DS2072 is the same as a DS2102 with simply a other sticker on the front is not true.
The DS2102 does out of the box about 150MHz, not so with an stock DS2072.........

I have not tested the A series.

[Wim13]

The chip they use has only switches for 20 -100 -200 -350 Mhz etc..

so there is no entry for 70 Mhz, what they do is playing with the gain a little. The differences are small.
You can see that when u do a measurment with a signal generator with a compensating head.

[SiC]

Just pumped the generated serial numbers from riglol into my brand new DS1074z - running on software version 00.04.00. They worked perfectly! I also tried uninstalling the keys using the SCPI interface and that works fine too - useful to know in case my 'scope ever needs to go back for repair.

Thanks guys for all the work on this and making it so incredibly easy.   
Also thanks Rigol for having a poor key implementation...!

Si.

[SiC]

I'll also add that I appear to have the latest version firmware on here. I did read that the 500uV option is buggy. In what way is it buggy?
On mine, the lowest 500uV setting, I get no trace shown at all.

Si.

[max666]

I'll also add that I appear to have the latest version firmware on here. I did read that the 500uV option is buggy. In what way is it buggy?
On mine, the lowest 500uV setting, I get no trace shown at all.

Si.

The offset is way off on the 500uV range, +10mV on mine. But if you don't mind scrolling it down ...

[Rigby]

and self-cal doesn't calibrate it, so it can't really be trusted at all, that kind of thing.  also, enabling it seems to cause other issues in the scope.

500uV is to be avoided on the DS1000Z scopes at this time.

[skytron]

Just received a new DS2072A-S with the AWG option installed.

 My question to the experts is:   Can I use the same firmware and upgrade procedure to upgrade this scope?   Has anyone done it?   

 
   I'm amazed and impressed with all the hard work done by some very smart people in creating so much value for us.

Thanks All.

[tsmith35]

Just received a new DS2072A-S with the AWG option installed.
My question to the experts is:   Can I use the same firmware and upgrade procedure to upgrade this scope?   Has anyone done it?

This may help: https://www.google.com/search?q=%22Sniffing+the+Rigol%27s+internal+I2C+bus%22+%22ds2072a-s%22