Author Topic: Rigol DS1054 or DS1202  (Read 1267 times)

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Offline dirtyfly

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Rigol DS1054 or DS1202
« on: August 07, 2020, 09:46:41 am »
Im replacing my failing 40MHz analog scope.

I never needed anything more than the dual 40MHz.

Now I cannot devide if I want 200MHz 2 channel or 50MHz 4 channels

price is the same.


Can anyone give me some insights to help me decide ?

thanks
 

Online Fungus

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Re: Rigol DS1054 or DS1202
« Reply #1 on: August 07, 2020, 10:19:13 am »
What do you use it for?

200Mhz isn't as great as it sounds unless you're using BNC cables. Probing 200Mhz with a standard probe is difficult.
 

Offline dirtyfly

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Re: Rigol DS1054 or DS1202
« Reply #2 on: August 07, 2020, 11:11:37 am »
thanks

I usally use it to debug retro computer and some ham radio stuff, never needed more than 35MHz

I'll be using the i2c and rs232 decoders that up to now ive used in my pc

Never used more than 2 channels.

If the 1054 was 100mhz there qwouldf be no doubt...

I'm afraid ill need more than 2 channls (cant imagine why :D
)

 

Online TurboTom

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Re: Rigol DS1054 or DS1202
« Reply #3 on: August 07, 2020, 11:13:45 am »
I'ld always have the four channels rather than higher bandwidth. Even the DS1054Z (hacked), with only one or two channels active has a considerable bandwidth margin over 100MHz. So, if the Rigol scope is otherwise okay for you, I'ld recommend to get the DS1054Z. There are other brands possibly offering better "alltogether" packages, but that's a different story, to be read in many other threads  ;).
 

Offline avlijas.sladjan

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Re: Rigol DS1054 or DS1202
« Reply #4 on: August 07, 2020, 11:17:17 am »
I write here on another post, my DS1054Z is +250MHz after upgrade with key (maybe I have luck, it is 4 year old). I think that any will be +140MHz and work very very good :)
 

Offline tv84

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Re: Rigol DS1054 or DS1202
« Reply #5 on: August 07, 2020, 11:33:27 am »
I write here on another post, my DS1054Z is +250MHz after upgrade with key (maybe I have luck, it is 4 year old).

FAKE NEWS. Please don't spread this BS without proving.
 

Online TurboTom

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Re: Rigol DS1054 or DS1202
« Reply #6 on: August 07, 2020, 11:44:20 am »
I write here on another post, my DS1054Z is +250MHz after upgrade with key (maybe I have luck, it is 4 year old).

FAKE NEWS. Please don't spread this BS without proving.

@tv84 is correct. 250MHz 3dB bandwidth is BS. You will see "something" @ 250MHz if only a single channel is active (1GSa/s) but for a "real" measurement, forget it. Here's some information that I could verify on my DS1000Z.

For general use, assume the 3dB point of the hacked DS1000Z to be at 135MHz (no more than two channels active, i.e. 500MSa/s). With all channels active, it's very advisavle to limit the highest frequency component of the input signal to 100MHz, otherwise you may end up with a lot of aliasing products.

Still, the four channel mode is pretty useful. Consider analyzing SPI protocols or even communicating with an I2C A/D or D/A converter and observing the serieal input contemporary with the analog output...
 
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Offline avlijas.sladjan

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Re: Rigol DS1054 or DS1202
« Reply #7 on: August 07, 2020, 12:08:08 pm »
Yes I measure with 1ch mode (99% use), and my instrument have rise time of 1.35 to 1.4ns.

Also read this (it is not my rigol)
https://hackaday.com/2016/10/05/choosing-a-scope-examining-bandwidth/
 

Online Fungus

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Re: Rigol DS1054 or DS1202
« Reply #8 on: August 07, 2020, 12:31:13 pm »
I'd go for four channels. You'll find uses for them if you have them.



 

Offline RoGeorge

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Re: Rigol DS1054 or DS1202
« Reply #9 on: August 07, 2020, 12:36:36 pm »
Yes I measure with 1ch mode (99% use), and my instrument have rise time of 1.35 to 1.4ns.

Also read this (it is not my rigol)
https://hackaday.com/2016/10/05/choosing-a-scope-examining-bandwidth/

That magic 0.35 formula is valid only for analog oscilloscopes.  The formula does not stand for digital oscilloscopes with much sharper DSP filters.  Also, what is shown on a digital oscilloscope is not the real signal, but a reconstruction of it after applying lots and lots of DSP.  Those 1.4ns are not the real raise time of the oscilloscope's amplifier.

DS1054Z is NOT a 250MHz analog bandwidth oscilloscope.



To answer the OP question, I'll buy the 4 channels one.

Online 2N3055

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Re: Rigol DS1054 or DS1202
« Reply #10 on: August 07, 2020, 12:39:58 pm »
Yes I measure with 1ch mode (99% use), and my instrument have rise time of 1.35 to 1.4ns.

Also read this (it is not my rigol)
https://hackaday.com/2016/10/05/choosing-a-scope-examining-bandwidth/

That is incorrect. You cannot estimate bandwidth like that, without knowing input characteristics.
Proper way is to make frequency sweep with leveled signal generator, which was done and cca 135 MHz is right figure.
 

Offline avlijas.sladjan

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Re: Rigol DS1054 or DS1202
« Reply #11 on: August 07, 2020, 12:53:07 pm »
- Analog bandwidth is the frequency at which the measured amplitude is 3 dB below the actual amplitude of the signal
- Rise time is the time required for a pulse to rise from 10 per cent to 90 per cent of its steady value

I remember that I measure only rise time, and it is about 1.4ns. Later I will check BW with signal generator, to be 100% like in definition :D
 

Offline avlijas.sladjan

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Re: Rigol DS1054 or DS1202
« Reply #12 on: August 07, 2020, 01:02:35 pm »

That magic 0.35 formula is valid only for analog oscilloscopes.  The formula does not stand for digital oscilloscopes with much sharper DSP filters.  Also, what is shown on a digital oscilloscope is not the real signal, but a reconstruction of it after applying lots and lots of DSP.  Those 1.4ns are not the real raise time of the oscilloscope's amplifier.


by the way for much sharper DSP filter with same rise time it will be more not less BW

https://www.tek.com/support/faqs/how-bandwidth-related-rise-time-oscilloscopes
 

Offline avlijas.sladjan

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Re: Rigol DS1054 or DS1202
« Reply #13 on: August 07, 2020, 07:09:47 pm »
A picture is worth a thousand words :D

 

Offline avlijas.sladjan

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Re: Rigol DS1054 or DS1202
« Reply #14 on: August 07, 2020, 07:11:45 pm »
Trigger is not very good after 150MHz, you will see phase noise. Also the counter is not working properly.
« Last Edit: August 07, 2020, 07:17:18 pm by avlijas.sladjan »
 

Offline uargo

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Re: Rigol DS1054 or DS1202
« Reply #15 on: August 08, 2020, 01:50:29 am »
A picture is worth a thousand words :D

 :palm: |O

The bandwidth of an oscilloscope is determined by several factors, mainly 3, if it does not meet the three parameters well, the result is that you are not seeing the correct signal.
Factors:

1 - Signal amplitude, when the signal falls 3db is the limit.
2 - Samples, you need at least 10 samples per cycle to be able to have a "real" signal. Really more, but that would be the minimum.
3 - Rise up and rise down time, you need it to be fast enough or it will distort the signal.

If only one of those factors fails, you will not see the real signal and it will not work correctly

other important factors are:
1 - The amount of WFMS / S that you are able to see.
2 - The "treatment" (falsified) that the oscilloscope does when interpreting the captured points and converting them into vectors to display a reconstructed signal. Rigol DS1054z in this falsifies more than other oscilloscopes



If you don't believe me, do an experiment:

First...
Put a 100Mhz SINE signal and capture it on the oscilloscope.
Now...
Put a TRIANGULAR signal of 100Mhz and you capture it, tell me if you can differentiate them?

Let's not say 200MHZ and much less 300MHZ
« Last Edit: August 08, 2020, 01:56:05 am by uargo »
 

Online 2N3055

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Re: Rigol DS1054 or DS1202
« Reply #16 on: August 08, 2020, 07:56:43 am »
A picture is worth a thousand words :D

 :palm: |O

The bandwidth of an oscilloscope is determined by several factors, mainly 3, if it does not meet the three parameters well, the result is that you are not seeing the correct signal.
Factors:

1 - Signal amplitude, when the signal falls 3db is the limit.
2 - Samples, you need at least 10 samples per cycle to be able to have a "real" signal. Really more, but that would be the minimum.
3 - Rise up and rise down time, you need it to be fast enough or it will distort the signal.

If only one of those factors fails, you will not see the real signal and it will not work correctly

other important factors are:
1 - The amount of WFMS / S that you are able to see.
2 - The "treatment" (falsified) that the oscilloscope does when interpreting the captured points and converting them into vectors to display a reconstructed signal. Rigol DS1054z in this falsifies more than other oscilloscopes



If you don't believe me, do an experiment:

First...
Put a 100Mhz SINE signal and capture it on the oscilloscope.
Now...
Put a TRIANGULAR signal of 100Mhz and you capture it, tell me if you can differentiate them?

Let's not say 200MHZ and much less 300MHZ


Er, no...
It is not that simple, yet it is simpler than that.


1. Yes, -3db point is considered bandwidth.  That is correct.
2. You need more than 2.5 samples per period of highest frequency sinewave component your input filtering will pass into A/D converter.
3. Rise/fall times and bandwidth are function of frequency/phase characteristics of  combined input attenuators/amplifiers/antialiasing filters all the way up to A/D converter(including A/D converter inputs).


4. Waveforms/seconds (triggers per second really) are important because of short retrigger time, so we can reliably trigger on quick short bursts (like in bursts of data packets on CAN bus for instance) without loosing data in a sequence.  For people working on slowly moving or simple repetitive signals not that important. But generally speaking shorter retrigger time is always better.
But, make note that is one of the specifications ALL manufacturers (even the A brand) are very "creative" with, and numbers will be applicable to very specific situations and timebases . Most of the time you will NOT get specced wfms/s.  I really wish that ALL manufacturers would simply publish table off retrigger times per time/div because that is all you need, really.
5. The "treatment" is called signal reconstruction.  It is important part of A/D conversion and D/A conversion of signal back to analog domain to display it on screen.

Realy, and pay attention here,  everybody thinks scope does A/D conversion and than creates data dots to display on screen.

It doesn't. It does A/D conversion, and then does D/A conversion of data back to analog domain. Except it doesn't convert it back to electric signal domain, but it converts it back to graphical, visual domain.
But to recreate signal as was seen by A/D converter (on it's input), you have to low pass filter output from D/A converter too. On a scope D/A converter/output filter is it's graphical plotting engine....

Scope is a band limited system. If you put a 100MHz squarewave or triangle wave into perfect 100 MHz oscilloscope you have to see something resembling sinewave on a screen in both cases.
Because scope have to filter out anything above 100MHz. 100 MHz scope is a 100MHz lowpass filter with screen...
And since any signal that has a repeating period of 100MHz that has any shape different than perfect sinewave, is a 100MHz sinewave with added harmonics at 2,3,4, 5, 6... times it's fundamental frequency (100MHz in this case), scope will filter those out and only show 100 MHz sinewave. Depending of spectral content of signal, you need scope with 5, 6, ...10.. times more bandwidth than signals repetition rate (fundamental frequency) to accurately show signal shape... 100 MHz triangle wave has significant harmonic content at 300, 500 and 700 MHz.... So you would need a 500Mhz scope to nicely show a 100 MHz triangle wave.
And that applies to analog scopes too. They are also band limited systems...
 

Offline RoGeorge

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Re: Rigol DS1054 or DS1202
« Reply #17 on: August 08, 2020, 08:16:56 am »
A picture is worth a thousand words :D







The amplitude response looks pretty good.  That property alone can serve well for some particular types of measurements, for example to look at an AM carrier, to measure modulation index, etc.  However, the amplitude response, alone, is not enough for an oscilloscope.

An oscilloscope is supposed to correctly show the shape of an arbitrary signal (composed of many spectral components, each with its own phase shift and own delays).  Preserving the phase of each spectral component is as important as the amplitude, in order to display the correct shape of an arbitrary waveform.  If the amplitude is correct for each frequency, but the phase is not, then the displayed shape will be very different from the original.  Same with the group delay vs frequency.

Would be interesting to measure phase shift vs frequency, too, and also the group delay vs frequency.
« Last Edit: August 08, 2020, 08:20:01 am by RoGeorge »
 

Online bd139

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Re: Rigol DS1054 or DS1202
« Reply #18 on: August 08, 2020, 09:10:14 am »
Definitely go 4 channels DS1054Z. It’s a massive advantage having more channels, particularly when working on serial protocols and more complex analogue systems and you’re already getting a bandwidth boost from your analogue scope.

With respect to bandwidth, if you’re doing HF ham stuff, then it’s fine for signal tracing and output monitoring. But really I’d probably reach for a NanoVNA more for radio stuff.

I would, as most of these infernal threads, ignore the semi-academic flame war that inevitably interlaces with the meat of the content.

If you want to save yourself some cash just buy another second hand analogue scope or fix yours :)
 

Offline avlijas.sladjan

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Re: Rigol DS1054 or DS1202
« Reply #19 on: August 08, 2020, 09:13:10 am »
If you want to buy perfect scope, sell Lamborghini, and buy maybe 20 high/middle/lowend (no one can have all with ideal specification). But for <1000$ scope all was good. I don't work for Rigol, and also buy this only to have one more toy in home :D. Also Analog is best buy todays, maybe to have one analog (100/200MHz old tek,HP is very cheap) with some digital.
Also before many years oscilloscopes have 100MHz with 100Msps, and 40GHZ with 200ksps, and no one says that is impossible. I know, we are want real time, 100Tsps for 100$, but maybe in our experiment 1Msps is max that we need :D

 

Online Fungus

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Re: Rigol DS1054 or DS1202
« Reply #20 on: August 08, 2020, 09:45:20 am »
2 - Samples, you need at least 10 samples per cycle to be able to have a "real" signal. Really more, but that would be the minimum.

Not true.
 
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Offline uargo

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Re: Rigol DS1054 or DS1202
« Reply #21 on: August 08, 2020, 09:57:47 am »
Er, yes but no.

1 - with only 2.5 samples per wave period you will see anything but not the actual wave.
It is a "convention" of the manufacturers but it is still false.
look here:
http://support.ircam.fr/docs/AudioSculpt/3.0/co/Sampling_1.html


2 - Wfms / s are very important to see glitches or other non-periodic wave failures

3 - The signal treatment carried out by the oscilloscope is important and normally falsifies the reconstruction looking for a sinusoidal finish (Rigol does it among many others)
https://circuitglobe.com/digital-storage-oscilloscope.html


4 - Digital oscilloscopes in general are rubbish because it is true that you need an oscilloscope with a frequency almost 10 times higher to see the real wave, this is so because the manufacturers considered that valid and as a standard, but it is rubbish that we have accepted.
Normally, 1GS ADC oscilloscopes are not able to distinguish a square signal from a sine wave beyond 25 or 30 Mhz, you can do the test yourself.

5 - It is false that analog oscilloscopes work the same, I have an analog one and taking it to the maximum bandwidth it is perfectly capable of differentiating between square, triangular or sinusoidal waves, and even seeing glitches.

Therefore I know what there is, I accept it reluctantly, but I know that a digital oscilloscope with a 1GS ADC does not see the real signal beyond about 30Mhz (using a single channel), that if they contribute many other things.

Therefore putting a photo of a Rigol ds1054Z with a signal of 100MHZ, 250MHZ and 300MHZ makes me laugh, you are seeing anything, but not reality.

I have a Siglent SDS1104X-E with 2 1GS ADCs and the same thing happens to it, beyond about 30MHz you do not distinguish square, sinusoidal or triangular signal, I see the fantasy that the oscilloscope wants to show, but not reality
« Last Edit: August 08, 2020, 10:02:03 am by uargo »
 

Online Fungus

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Re: Rigol DS1054 or DS1202
« Reply #22 on: August 08, 2020, 10:00:25 am »
I have a Siglent SDS1104X-E with 2 1GS ADCs and the same thing happens to it, beyond about 30MHz you do not distinguish square, sinusoidal or triangular signal, I see the fantasy that the oscilloscope wants to show, but not reality

If I were you I'd sell it and buy a Rigol MSO5000.
 

Offline uargo

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Re: Rigol DS1054 or DS1202
« Reply #23 on: August 08, 2020, 10:10:24 am »
I have a Siglent SDS1104X-E with 2 1GS ADCs and the same thing happens to it, beyond about 30MHz you do not distinguish square, sinusoidal or triangular signal, I see the fantasy that the oscilloscope wants to show, but not reality

If I were you I'd sell it and buy a Rigol MSO5000.

I can't buy a Rigol MSO5000, it is too expensive for me, but I have no stupid illusions putting a picture of a DS1054Z at 300MHZ saying "measure it"
 

Online TurboTom

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Re: Rigol DS1054 or DS1202
« Reply #24 on: August 08, 2020, 10:19:49 am »
A picture is worth a thousand words :D

Unless your scope is fundamentally different from all the other DS1000Z known to me, these photos are fake. What is your vertical multiplier? My DS1000Z switches ranges between 330 and 335 mV/div (at 1x multiplier). At 335mV/div and above, I can duplicate your findings, below, the 3dB bandwidth is about 135MHz. See the link to the DS1000Z main thread from my previous contribution.
 


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