Author Topic: New Rigol DS1054Z oscilloscope  (Read 1457193 times)

0 Members and 1 Guest are viewing this topic.

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4175 on: September 06, 2018, 06:44:49 pm »
One may say Rigal is "cheating" in the DS1000Z, and strictly speaking that's probably correct. But what difference does it make for the average hobby user working on audio or low-speed microcontroller stuff? I guess the result is still good enough for the job, if something better is really necessary, the options are plentiful.

If it is just a hobby - no difference whatsoever. But for student it might be a problem if he is trying to learn (analog stuff) and phenomenon on the screen is not "by the book". Anyway here is old PDF which explains it all:

https://www.eevblog.com/forum/testgear/rigol-ds1054z-bandwidth/?action=dlattach;attach=280275

Basic idea was to sweep 20...120MHz and plot amplitude response in different modes. Demodulator probe is used to check actual amplitude directly on scope input. Demod is low capacitance and does not affect operation. As seen physical amplitude on input has expected shape - slow rolloff. However phenomenon on the screen is wildly varying from very steep rolloff (Sinc=OFF) to rising amplitude with rising frequency. This "software boost" tech is cause for unrealistic rise time measurements. With Sinc=ON there is general correlation for higher voltage ranges: less datapoints per edge - more artificial steepening of the slope. Yet again different behaviour for low ranges... Quite complex mess to navigate... price for low price.

Example from PDF:

For 500mV/div reported amplitude is rising from 20 to 60MHz. Yet actually it is falling just like it should, measured directly on BNC connector (dotted lines).

Certainly there is range of tasks where this is not a problem. For other tasks - showstopper. So best if information is out there and anyone can make informed decision and not just fall for pretty knobs and general hype.
« Last Edit: September 06, 2018, 06:57:36 pm by MrW0lf »
 
The following users thanked this post: TurboTom

Offline rf-loop

  • Super Contributor
  • ***
  • Posts: 3059
  • Country: fi
  • Country: fi
  • Starting with DLL21
Re: New Rigol DS1054Z oscilloscope
« Reply #4176 on: September 06, 2018, 06:57:58 pm »
To add more to the confusion, here are some screenshots of my "liberated" 1054Z, fed with a signal from a Leo Bodnar fast edge square generator through a 50R BNC terminator to channel 1 (the other channels perform identical). The scope was configured in dot mode and fine vertical control. The single input divider relay of the DS1000Z switches between 330 and 335mV/div and this makes a big difference: at 335mV selection, the input amplifier "sees" much less signal and the VGA integrated in the A/D converter is adjusted at high gain. I kept that as a reference trace while I changed input sensitivity to 330mV, resulting in the input amp being driven with a much larger signal. The trace shapes and rise times differ by more than 1ns, but both appear to be well within the 100MHz range.

I also took a reading at 250MSa/s. Funny enough, the input divider relay is now actuated between 250 and 245mV/div. The difference of the rise time between the two settings now is neglible but something ugly goes on with the sin(X)/x trace reconstruction. It becomes obvious that even in dot mode (not only vector display), the 'scope uses this correction function (or something else...maybe a high pass filter to compensate for the input amp's high frequency dropoff) to modify the data readings. Unfortunately, the sin(x)/x "optimization" can only be disabled at 250MSa/s so it's difficult to get a better understanding of what kind of mathematical methods are used (see the third and fourth screenshots).

One may say Rigal is "cheating" in the DS1000Z, and strictly speaking that's probably correct. But what difference does it make for the average hobby user working on audio or low-speed microcontroller stuff? I guess the result is still good enough for the job, if something better is really necessary, the options are plentiful.

Are there any differences between the DS1054Z and DS1104Z models hardware-wise? Possible, but I doubt it. The instrument is too inexpensive for the manufacturer to go through the hassle of component or instrument selection.

Cheers,
Thomas

Something about Sin(x)/x... and Rig(x)/x what mess have continued nearly 10 years. Hopeless.
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 

Offline CatalinaWOW

  • Super Contributor
  • ***
  • Posts: 3152
  • Country: us
  • Country: us
Re: New Rigol DS1054Z oscilloscope
« Reply #4177 on: September 06, 2018, 07:57:54 pm »
Your measurements show a plus or minus 1.3 dB difference between the all the different conditions at the highest frequency.  While there are cases where 1.3 dB is a showstopper, there are many, many more where it will be lost in the noise.  If you really want to measure things an oscilloscope, no matter what it's pedigree, is rarely the right tool.  An oscilloscope is primarily a visualization tool, with some capability to make low precision measurements.
 
The following users thanked this post: ankerwolf

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4178 on: September 06, 2018, 08:29:19 pm »
Your measurements show a plus or minus 1.3 dB difference between the all the different conditions at the highest frequency.

Did you even look at PDF?   :-//

@100MHz

3.500V gen out displayed.

Demod reports 3.147V on gen (scope not connected), 2.841V on scope connector. Note that demod lowers value and is for relative not absolute measurements.

Scope reads:
3.440V at 1GSa/s, Sinc
2.080V at 250MSa/s, w/o Sinc

Sink it in. ~2V vs ~3.5V!!! When twisting knobs that should only affect signal fidelity, not amplitude.
« Last Edit: September 06, 2018, 08:33:43 pm by MrW0lf »
 

Offline rf-loop

  • Super Contributor
  • ***
  • Posts: 3059
  • Country: fi
  • Country: fi
  • Starting with DLL21
Re: New Rigol DS1054Z oscilloscope
« Reply #4179 on: September 06, 2018, 09:05:22 pm »
Your measurements show a plus or minus 1.3 dB difference between the all the different conditions at the highest frequency.

Did you even look at PDF?   :-//

@100MHz

3.500V gen out displayed.

Demod reports 3.147V on gen (scope not connected), 2.841V on scope connector. Note that demod lowers value and is for relative not absolute measurements.

Scope reads:
3.440V at 1GSa/s, Sinc
2.080V at 250MSa/s, w/o Sinc

Sink it in. ~2V vs ~3.5V!!! When twisting knobs that should only affect signal fidelity, not amplitude.

Here small part from my tests year 2014

Signal 70MHz pure sine and exatly same input level in both images. Why 70MHz. Because at this time I use  DS1074Z. This freq is not so important.

Important is that oscilloscope itself do this level step without any change in signal level, freq or shape or any other things but t/div change and without even samplerate change.

And this affect level change. Totally wrong, so totally that I can ask, what hell they are smoking in Rigol when they design. I repeat. Signal is exatly same. If nothing other but this make it special severe and tell that design is wrong.
Only change is timebase. Samplerate also do not change. (then if continue from 100ns to 5ns/div it keep this changed level level.)

(in same old thread where from are these images, there is more things but this total mess with Sin(x)/x is really mad. Why do wrong because it is so simple do right. Now they need name it Rig(x)/x what they first time implement to DS1052E ten years ago and also at this time tested and proofed that they did it wrong (Sinc iterpolation rule violation) . It is same question or not with this level drop but least somehow they are hand in hand relatives. I do not know how exactly.)

But disclaimer: This test is old. I do not know if this have changed after many FW repairs. Someone can check.


200n-dots-sinxOff.png


100n-dots-sinxOff.png


"Rigol oscilloscope is primarily visualization tool" (others are analyzers and mesurement tools for characterize less or more unknown signal.)

Rigol is like watching sky using this "tool"...  look in and it show you what it like show...

https://en.wikipedia.org/wiki/Kaleidoscope#/media/File:Kaleidoscope_San_Diego.jpg
« Last Edit: September 06, 2018, 09:41:59 pm by rf-loop »
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 
The following users thanked this post: MrW0lf

Offline Supernick

  • Contributor
  • Posts: 12
  • Country: by
  • Country: by
Re: New Rigol DS1054Z oscilloscope
« Reply #4180 on: September 06, 2018, 09:10:14 pm »
I will write a direct message to the Rigol and ask whether it is possible to hack ds1054z and what consequences  :)
 

Online xrunner

  • Super Contributor
  • ***
  • Posts: 3971
  • Country: us
  • Country: us
  • hp>Agilent>Keysight>?
Re: New Rigol DS1054Z oscilloscope
« Reply #4181 on: September 06, 2018, 09:37:27 pm »
I will write a direct message to the Rigol and ask whether it is possible to hack ds1054z and what consequences  :)

This old saying comes to mind -

"Let sleeping dogs lie"
I am a Test Equipment Addict (TEA) - by virtue of this forum signature, I have now faced my addiction
 
The following users thanked this post: tooki

Offline tv84

  • Frequent Contributor
  • **
  • Posts: 791
  • Country: pt
  • Country: pt
Re: New Rigol DS1054Z oscilloscope
« Reply #4182 on: September 06, 2018, 10:03:07 pm »
I will write a direct message to the Rigol and ask whether it is possible to hack ds1054z and what consequences  :)

:-//

I insist that if you all called it "unlock" instead of "hack" all would live less worried...

The individual man hours spent discussing this subject are worth more (in cash) than the money needed to buy a better scope!!

If you want a 50MHz scope with the intention of upgrading to 100MHz because it's a good bargain, just accept all/any limitations that strategy may imply (if any)!!
 

Offline CatalinaWOW

  • Super Contributor
  • ***
  • Posts: 3152
  • Country: us
  • Country: us
Re: New Rigol DS1054Z oscilloscope
« Reply #4183 on: September 06, 2018, 10:47:13 pm »
Your measurements show a plus or minus 1.3 dB difference between the all the different conditions at the highest frequency.

Did you even look at PDF?   :-//

@100MHz

3.500V gen out displayed.

Demod reports 3.147V on gen (scope not connected), 2.841V on scope connector. Note that demod lowers value and is for relative not absolute measurements.

Scope reads:
3.440V at 1GSa/s, Sinc
2.080V at 250MSa/s, w/o Sinc

Sink it in. ~2V vs ~3.5V!!! When twisting knobs that should only affect signal fidelity, not amplitude.

I just looked at the chart you posted.  Using the numbers your are whining about (3.4 and 2.0) it is plus or minus 2 dB.  Not great, but I'll stand by the other comments.
 

Offline technogeeky

  • Frequent Contributor
  • **
  • Posts: 540
  • Country: us
  • Country: us
  • Older New "New Player" Player Playa'
Re: New Rigol DS1054Z oscilloscope
« Reply #4184 on: September 07, 2018, 04:01:07 am »
...


200n-dots-sinxOff.png


100n-dots-sinxOff.png

I am not totally sure what the complaint is in this post, but I noticed that it was disclaimed as an old test. I think the complaint is the amplitude change when sin(x)/x is off on dots mode. So I made some animations of a current oscilloscope with the 2nd to latest firmware.


* 20 MHz sine wave (I can't generate a 70MHz sine wave easily)
* DOTS mode
* intensity 91%

sin(x)/x off - 100ns/div to 100ms/div


sin(x)/x on - 100ns/div to 200ms/div


sin(x)/x on with AA - 100ns/div to 100ms/div


I would conclude from these that there is no change in amplitude when changing the timebase. It's not possible to see from these captures, but there is a slight change in amplitude from sin(x)/x on to sin(x)/x off. But it's slight.

« Last Edit: September 07, 2018, 04:03:35 am by technogeeky »
 

Offline technogeeky

  • Frequent Contributor
  • **
  • Posts: 540
  • Country: us
  • Country: us
  • Older New "New Player" Player Playa'
Re: New Rigol DS1054Z oscilloscope
« Reply #4185 on: September 07, 2018, 04:45:21 am »
I wanted to cross-post in here to point out that the newest version of Rigol Bildschirmkopie is available which has precise control of screenshot capturing which allows for nicer video output and smoother videos from the Rigol 1054z (and presumably other Rigol instruments). It was previously a problem when capturing "as fast as possible" because the scope would skip important work (like FFT) in favor of sending screenshots. But this has been fixed as exemplified here.
 

Offline rf-loop

  • Super Contributor
  • ***
  • Posts: 3059
  • Country: fi
  • Country: fi
  • Starting with DLL21
Re: New Rigol DS1054Z oscilloscope
« Reply #4186 on: September 07, 2018, 04:58:05 am »
@ technogeeky
Because I want know truth and also I want of course change my opinion about this situation if the new information overrides the old one.

So, if looks that finally they have repaired this level change. (ETA: look bottom)

But then it is also interesting if they have also repaired old Sin(x)/x fake.

Simply - one very important major rule is. Interpolation result line goes through every samplepoint.
It have been problem in old DS1000E and then later in DS1000Z.
But as told last test I have done years ago.

ETA: oh no! Now my old eyes find this what makes it questionable until more comparable data:
Quote
* 20 MHz sine wave (I can't generate a 70MHz sine wave easily)
« Last Edit: September 07, 2018, 04:56:33 pm by rf-loop »
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 

Online BravoV

  • Super Contributor
  • ***
  • Posts: 5947
  • Country: 00
  • Country: 00
Re: New Rigol DS1054Z oscilloscope
« Reply #4187 on: September 07, 2018, 06:26:30 am »
Because I want know truth and also I want of course change my opinion about this situation if the new information overrides the old one.

Dunno why, have a feeling that you will only change your opinion once you become a Rigol distributor, instead of current Siglent, really wish one day you carry both at your shop, as I respect your technical experiences at oscilloscopes especially at the boat anchor types.

Offline borjam

  • Supporter
  • ****
  • Posts: 719
  • Country: es
  • Country: es
  • EA2EKH
Re: New Rigol DS1054Z oscilloscope
« Reply #4188 on: September 07, 2018, 07:21:15 am »
Most probably sin(x)/x was on when testing, or some other acquisition settings were different between the two 'scopes.
You can't disable it unless you enable several channels. That's an oddity.
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 15662
  • Country: nz
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: New Rigol DS1054Z oscilloscope
« Reply #4189 on: September 07, 2018, 08:19:22 am »
Because I want know truth and also I want of course change my opinion about this situation if the new information overrides the old one.

Dunno why, have a feeling that you will only change your opinion once you become a Rigol distributor, instead of current Siglent, really wish one day you carry both at your shop, as I respect your technical experiences at oscilloscopes especially at the boat anchor types.
You need to know some long standing, very knowledgeable and respected members better; from 2014:

Quote
I sell also Owon and have previously sold Hantek and Rigol.
(also Owon have very low failure rate but not exatly zero but ~1%)

Hantek - so much warranty time problems and also so much just DOA units from factory. Never want this catastroph repeating. In worst phase incoming Hanteks failure percent in my quality control was well over 25% (~40%). (depending how to count lots).  It was finally -  game over.

Rigol - long time ago I sell also R. -  never get any answer from Rigol for solve any problems. So, I stopped.   In  my own use for some dedicated purpose  I have also new Rigol (1000Z series) but I do not even think to sell these.

https://www.eevblog.com/forum/testgear/are-siglent-oscilloscopes-reliable/msg576620/#msg576620
Avid Rabid Hobbyist
 

Online Fungus

  • Super Contributor
  • ***
  • Posts: 9867
  • Country: 00
  • Country: 00
Re: New Rigol DS1054Z oscilloscope
« Reply #4190 on: September 07, 2018, 08:32:21 am »
Scope reads:
3.440V at 1GSa/s, Sinc
2.080V at 250MSa/s, w/o Sinc

Sink it in. ~2V vs ~3.5V!!! When twisting knobs that should only affect signal fidelity, not amplitude.

Ummm... let's see if I've got this straight:

What you're saying is that when you sample a signal then don't do a proper sinc reconstruction, the answer is wrong? Is that correct?

Mr. rf-loop seems to agree:

First 3 images:
200ns/div ; Sin(x)/x  OFF  scope show normal level (as also with more low speeds)
100ns/div ; Sin(x)/x  OFF  level drops down and then stay same level from this speed down to 5ns/s
005ns/div ; Sin(x)/x  OFF level drops down
Next 3 images:
200ns/div ; Sin(x)/x  ON  level ok (as also with more low speeds)
100ns/div ; Sin(x)/x  ON  level ok
005ns/div ; Sin(x)/x  ON  level ok

Also if think typical criteria for sin(x)/x interpolation there is 250MSa/s and input is 70MHz sinewave. Samplerate/input frequency = 3.57 what is ok. Even with 100MHz it is still in acceptable range (2.5)

sin(x)/x=ON gives correct answers? Go figure. :palm:

Worse: You're doing this "analysis" on an oscilloscope that only lets you disable sin(x)/x when it knows that there's not many samples per MHz (ie. when it goes down to just 2.5 samples per wave), all the rest of the time sin(x)/x is forced on. (I wonder why Rigol would do that? Hmmm...  :horse: )

And (b): You have to use "dot" mode to even see the problem - which nobody in their right mind would ever do.

ie. This has no practical effect on any usage scenario that would happen in real life.

Me? I think the real problem here is in the heads of the people who waste everybody's time with this junk (and on a $350 oscilloscope, too!)
« Last Edit: September 07, 2018, 08:39:44 am by Fungus »
 

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4191 on: September 07, 2018, 11:43:06 am »
Now they need name it Rig(x)/x

:clap:

https://dictionary.cambridge.org/dictionary/english/rig

Quote
to arrange dishonestly for the result of something, for example an election, to be changed


 

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4192 on: September 07, 2018, 11:50:52 am »
* 20 MHz sine wave (I can't generate a 70MHz sine wave easily)

If you look my tests it is pretty adequate at that frequency, circus starts at about 50MHz when number of samples per wfm feature gets low and rig(x)/x kicks in heavily. So if analog-related tasks lie below 50MHz no prob.
 

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4193 on: September 07, 2018, 12:06:15 pm »
What you're saying is that when you sample a signal then don't do a proper sinc reconstruction, the answer is wrong? Is that correct?

Are you implying that "proper sinc reconstruction" is rising signal level over 4dB compared to actual recorded sample points?
Also you seem to be on position that signal max amplitude should be somehow related to sampling rate (of course given some minimal sufficient set of points to account for aliasing etc).
Is it so?  ::)
 

Online Fungus

  • Super Contributor
  • ***
  • Posts: 9867
  • Country: 00
  • Country: 00
Re: New Rigol DS1054Z oscilloscope
« Reply #4194 on: September 07, 2018, 12:45:23 pm »
Are you implying that "proper sinc reconstruction" is rising signal level over 4dB compared to actual recorded sample points?
Also you seem to be on position that signal max amplitude should be somehow related to sampling rate (of course given some minimal sufficient set of points to account for aliasing etc).
Is it so?  ::)

Where are you getting "actual recorded sample points" from?
 

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4195 on: September 07, 2018, 12:49:47 pm »
Quote from: Fungus link=topic=36920.msg1806275#msg1806275
Where are you getting "actual recorded sample points" from?

One should be getting then from Sinc=OFF trace...
 

Online Fungus

  • Super Contributor
  • ***
  • Posts: 9867
  • Country: 00
  • Country: 00
Re: New Rigol DS1054Z oscilloscope
« Reply #4196 on: September 07, 2018, 01:00:11 pm »
Quote from: Fungus link=topic=36920.msg1806275#msg1806275
Where are you getting "actual recorded sample points" from?

One should be getting then from Sinc=OFF trace...

Yes, but but it's not a legal requirement and we know that in this particular case one isn't.

That means your little "analysis" is all ass-backward and your conclusions are wrong.

Worse: You know all this, hence your emphasis of the word "should", above.
 

Offline metrologist

  • Super Contributor
  • ***
  • Posts: 1764
  • Country: 00
  • Country: 00
Re: New Rigol DS1054Z oscilloscope
« Reply #4197 on: September 07, 2018, 01:06:02 pm »
Did you even look at PDF?   :-//

It would be more interesting if I knew more about your test setup and equipment. What's the uncertainty of the signal flatness and then of the system? Are you relying on the flatness of a signal generator sweep or are you leveling at the input?
 

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4198 on: September 07, 2018, 01:16:54 pm »
It would be more interesting if I knew more about your test setup and equipment. What's the uncertainty of the signal flatness and then of the system? Are you relying on the flatness of a signal generator sweep or are you leveling at the input?

Heres original post with all details including raw data in Excel:
https://www.eevblog.com/forum/testgear/rigol-ds1054z-bandwidth/msg1097348/#msg1097348

Flatness was recorded and checked:
Look green tables named "demod on gen CH1"
Testec TT-DE 112 950MHz demod (some tests here) & Agilent U1272A was used to check voltages between gen and scope (BNC T after 50ohm pass-thru).
If was double checked that demod had no effect on display values.
Generator was Siglent SDG2042X in 120MHz flavour and has excellent flatness.
« Last Edit: September 07, 2018, 01:48:55 pm by MrW0lf »
 

Offline MrW0lf

  • Frequent Contributor
  • **
  • Posts: 921
  • Country: ee
  • Country: ee
    • lab!fyi
Re: New Rigol DS1054Z oscilloscope
« Reply #4199 on: September 07, 2018, 01:24:16 pm »
Yes, but but it's not a legal requirement and we know that in this particular case one isn't.

Good business to consumer relationship is about trust and following best practices, not legal requirements...
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf