Author Topic: buy a better oscilloscope than the Siglent SDS1104X-E  (Read 12334 times)

0 Members and 1 Guest are viewing this topic.

Offline rf-loop

  • Super Contributor
  • ***
  • Posts: 4135
  • Country: cn
  • Born in Finland with DLL21 in hand
Re: buy a better oscilloscope than the Siglent SDS1104X-E
« Reply #75 on: August 19, 2023, 09:07:21 am »
Here is one quite old image. At this time I own one Rigol 1074Z (mod to 1104Z)
In upper part of image (Rigol) there is also note about data used to measurements, today we know more also about this and it really use very extremely tiny intermediate buffer for measurements when Siglent use full acquisition data.

And then bottom part of image Siglent SDS1104X-E. Settings as same as possible what was used with Rigol for fair compare.
1mV/dif used because Rigol did not have 500uV/div. (also 1mV/div in Rigol is not true full resolution, it is some kind of production from 5mV/div)
Around 60uV AC RMS (Stdev) is quite good for 100+ MHz bandwidth with 1Mohm inputs.
Typically it is much better than service manual "go to repair" limit.

This is many years old..
Also I have measured several SDS1104X-E and I really can say that common value at 500uV/div is between 50 - 65uV/div  Stdev (AC RMS)




EV of course. Cars with smoke exhaust pipes - go to museum.
Wises must compel the mad barbarians to stop their crimes against humanity. Where have the (strong)wises gone?
 
The following users thanked this post: Performa01

Offline Performa01

  • Super Contributor
  • ***
  • Posts: 1729
  • Country: at
Re: buy a better oscilloscope than the Siglent SDS1104X-E
« Reply #76 on: August 19, 2023, 09:10:32 am »
I have put the FFT in the table, look well,
Well, yes, I've overlooked it in this messy table. FFT is normally characterized in points, not bytes and there are still some other parameters to consider.

Btw, your table contains a Siglent SDS1104X HD - a scope which doesn't exist outside China. Currently, nobody will be able to tell you what exactly we (the rest of the world) will be getting. However, I can assure you that it will be worth waiting for - if you really need a high resolution oscilloscope and don't mind a clumsy solution for the digital channels, like on the SDS1104X-E.

I have been researching on the internet to obtain the background noise of the SDS1104X-E and the only thing I have found is that it is:

Table 8 Noise Floor Limited Range for 2-Channel
Volt/Div        Stdev Limited Range
500 uv         ≤ 250 uv

link:https://int.siglent.com/upload_file/user/SDS1000X-E/SDS1000X-E_ServiceManual_SM0101E-E01A.pdf
This is a generic tolerance window for all SDS1000X-E series scopes, including the 200 MHz models, which have an actual bandwidth of ~240 MHz (SDS1104X-E: 110 MHz). The margins are wide; even though the SDS1000X-E are low noise like all contemporary Siglent scopes, Siglent quite obviously isn't willing to guarantee this for their bottom entry level scopes.

and where do you get that it has 56uVrms ( better even than the $4,600 12-bit 350Mhz SDS2354X HD which has 70uVrms)
Quite simple. I've measured it.

It is clear that my oscilloscope and yours, even though they are the same model, have different characteristics.
No. In theory, there could be slight differences, but since it's an easy task, many people have measured the noise of their SDS1000X-E and there never has been any significant discrepancy.
Hint: a 200 MHz device should show about 50% more noise, i.e. about 84 µVrms.
 

Online Martin72

  • Super Contributor
  • ***
  • Posts: 7019
  • Country: de
  • Testfield Technician
Re: buy a better oscilloscope than the Siglent SDS1104X-E
« Reply #77 on: August 19, 2023, 12:25:56 pm »
At the moment I let the SDS1104X-E warm up for it...

Did it now, "yesterday" it was too late...
@uargo:
Important is to make a selfcal before, pic 1 shows the traces after switching the scope on.
Then warmup for appx 30min, then let the scope performing the selfcal, pic 2 show the result after.
Took channel 2, 500µV/div., 1ms/Div., no shielding at all, no averaging.



Offline Performa01

  • Super Contributor
  • ***
  • Posts: 1729
  • Country: at
Re: buy a better oscilloscope than the Siglent SDS1104X-E
« Reply #78 on: August 19, 2023, 01:42:52 pm »
    At the moment I let the SDS1104X-E warm up for it...

    Did it now, "yesterday" it was too late...
    A few remarks:
    • Even more important than the total bandwidth is the lower bandwidth limit, due to the 1/f noise characteristics. At 1 ms/div the lower bandwidt limit is ~70 Hz on an SDS1000X-E. This will of course yield significantly worse results than a measurement at e.g. 1 µs/div and ~70 kHz lower bandwidth limit. We can also take the current record length as a criterion (and 1.4 Mpts is a massive amount of data), but specifying the lower bandwidth limit is a much more robust statement.
    • It has been mentioned over and over again: RMS is the wrong measurement for noise. If we use Stdev instead (on some DSOs it's called AC-RMS), then we need not worry about DC offsets and neither have to wait half an hour nor do a self-cal just because we want to measure noise. Apart from that, even with a fresh self-cal there will still be some remaining offset error which will be erroneously interpreted as noise when using the RMS measurement.
    • Many scopes do not have 500 µV/div sensitivity (some even have only 4 or 5 mV/div and use digital zoom to fake higher sensitivity). So I recommend to use 1 mV/div throughout. It's a more fair comparison because of a near identical dynamic range for all contenders and it is visually better comparable as well.
    • Your measurement appears to be in the right ballpark (61 µVrms) for full bandwidth, which could easily drop to 56 µVrms once you use the right measurement (Stdev).
    • Your measurement with 20 MHz bandwidth limiter appears much too high (55 µVrms), where I have no other explanation than that is caused by an DC offset error. It would be nice to see a Stdev measurement to confirm my theory.
    • Finally I want to repeat what rf-loop already mentioned: The Siglent always measures the entire record, hence 1.4 Mpts is this example. "Measurements" that  only use decimated (screen) data will just provide street numbers, because decimation alters the bandwidth.
    « Last Edit: August 20, 2023, 01:12:01 pm by Performa01 »
     
    The following users thanked this post: Martin72

    Online Martin72

    • Super Contributor
    • ***
    • Posts: 7019
    • Country: de
    • Testfield Technician
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #79 on: August 19, 2023, 02:24:10 pm »
    Quote
    A few remarks:

     ;)

    Can repeat it with the wanted parameter.
    « Last Edit: August 19, 2023, 04:17:02 pm by Martin72 »
     

    Offline uargoTopic starter

    • Regular Contributor
    • *
    • Posts: 102
    • Country: es
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #80 on: August 19, 2023, 04:01:32 pm »
    Quote
    better even than the $4,600 12-bit 350Mhz SDS2354X HD which has 70uVrms

    65µVrms, look at the datasheet.
    And: Noise rises more or less with the bandwith.
    Plus: The difference between 56µVrms and 65µVrms is....nothing.
    Plus, the second: You already have a SDS1104X-E, so you can measure it in real and now. ;)
    At the moment I let the SDS1104X-E warm up for it...

    I put a link to the siglent document that supports what I say, can you do the same, please
     

    Online Martin72

    • Super Contributor
    • ***
    • Posts: 7019
    • Country: de
    • Testfield Technician
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #81 on: August 19, 2023, 04:14:06 pm »
    LOL...OK, look at the pic below.

    Quote
    Can repeat it with the wanted parameter.

    All channels, history mode, 20Mhz bw limit, picking the lowest value.

    (damn...500µV/div. ....)
    « Last Edit: August 19, 2023, 04:16:43 pm by Martin72 »
     

    Offline rf-loop

    • Super Contributor
    • ***
    • Posts: 4135
    • Country: cn
    • Born in Finland with DLL21 in hand
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #82 on: August 19, 2023, 04:30:49 pm »

    Interesting.
    How can I make sure that not only the screendata will be used for the values ? The history record ?


    How you can be sure. Very Simply. Just believe what we tell about it. (but do not believe everyone --- you know....)

    But if you do not trust, you can also easy evaluate it. 
     

    You can somehow test if it use decimation for display is using example slow timebases and narrow  pulses. If it decimate before display there start missing some these pulses. Not happen with Siglent. But one vertical column can have many of these pulses overlaid on screen (example if burst include many pulses but whole burst is only one display pixel width. (all pulses overlayed in this column)).  But still measurement can see separate pulses. 


    Some oscilloscope measure using screen mapped data and then  there is max resolution same as screen resolution.
    Some oscilloscopes may use this screen (mapped) data for measure.
    Some scopes may use some other kind of intermediate buffer for measurements. More resolution than display resolution but less than is in sample buffer (depending time base etc).
    There is also some older Siglent models what use intermediate buffer for measurements (example SDS1000X models because there is not brute force for handle full resolution full data length measurements)

    This SDS1104/1204X-E use full sample buffer for measurements (just this memory length what display info screen tell about current memory length).

    I think if you do some simple tests it tell lot of about this.

    Idea is just that input signal have more time domain events than  than display resolution is. You can easy find many kind of signals for test it.
    Here one example...  no need just this... 
    Simplest is 10MHz sine and scope 1ms/div and then measurements about +width, interval etc etc... scopes what use display buffer fails here totally.

    Set 1ms/div.
    Produce signal what have 50ns width pulses and pulses period 1.001us (1001ns) and risetime example 15ns
    Set measure for Period  and +Width and risetime.

    If oscilloscope use screen buffer for measurement... All these measurements fails totally.

    If horizontal resolution is example 700 pixel and 14 div (as is in SDS1000X-E models)
    If 1ms/div, then 1 div pixel resolution is 20us. (time axis 50 pixel/div)   

    But in this example measurement display pulse width around 50ns and period around 1001ns and also risetime based to 1ns resolution (because sampling interval is 1ns and because it use full acquistion resolution.

    Ok do it use also really full length of data. Yes. You can easy test it... make signal so that nearly start of sample buffer is one pulse and nearly end of buffer next pulse (example 13ms interval, 50ns pulses. Set trigger half div after display left border. Yes you get 13us interval so lenght used for measurement is least this , you can see next pulse half div before right border and as you can see resolution for interval is 1ns.

    Try with Rigol 1000Z. Also you can try with some Megazoom Keysight.  (no need test, I can tell situation is just "game over")

    But one note. Example in this case. There is not Interpolation between true sample points in this case. So resolution is now sample interval. 

    Long time ago here in forum was some very long thread about this measurement resolution with different oscilloscopes and also something about testing it. In this thread there is lot of data and information.
    Fast searching I didn't find it.

    « Last Edit: August 19, 2023, 04:49:07 pm by rf-loop »
    EV of course. Cars with smoke exhaust pipes - go to museum.
    Wises must compel the mad barbarians to stop their crimes against humanity. Where have the (strong)wises gone?
     
    The following users thanked this post: Martin72

    Online Martin72

    • Super Contributor
    • ***
    • Posts: 7019
    • Country: de
    • Testfield Technician
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #83 on: August 19, 2023, 05:06:49 pm »
    Very interesting things, I need to read this in peace and find out more.
    It's like a rabbit hole... 8)

    Actually, I wanted to repeat the measurements with 1mV/div. but I don't feel like it today, especially since the offset from the scope keeps "running away" from me.
    At some point, that's no longer any fun. ;)
    But it's not mine, my HD is very easy to care for.

    Offline uargoTopic starter

    • Regular Contributor
    • *
    • Posts: 102
    • Country: es
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #84 on: August 19, 2023, 07:24:19 pm »
    LOL...OK, look at the pic below.

    Quote
    Can repeat it with the wanted parameter.

    All channels, history mode, 20Mhz bw limit, picking the lowest value.

    (damn...500µV/div. ....)

    the capture that you have put is at 50 ohm, of the SDS2104X HD model, THAT DATA OF THE SDS1104X-E does not exist published by Siglent. If you say that empirically it is that, then it will be, measuring the noise gives me unstable readings and strange things at those levels
     

    Online Martin72

    • Super Contributor
    • ***
    • Posts: 7019
    • Country: de
    • Testfield Technician
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #85 on: August 19, 2023, 08:25:30 pm »
    Hm ?

    Quote
    ( better even than the $4,600 12-bit 350Mhz SDS2354X HD which has 70uVrms)

    That´s what you´ve wrote, I don´t know from which datasheet you got this information because it´s 65µVrms.
    You asked me where I have this information, I´ve posted a snip from the datasheet.

    Quote
    the capture that you have put is at 50 ohm, of the SDS2104X HD model,

    No Sir, the SDS2104X HD have 50µVrms, look again..


    Online 2N3055

    • Super Contributor
    • ***
    • Posts: 7464
    • Country: hr
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #86 on: August 19, 2023, 08:58:59 pm »
    Quote
    better even than the $4,600 12-bit 350Mhz SDS2354X HD which has 70uVrms

    65µVrms, look at the datasheet.
    And: Noise rises more or less with the bandwith.
    Plus: The difference between 56µVrms and 65µVrms is....nothing.
    Plus, the second: You already have a SDS1104X-E, so you can measure it in real and now. ;)
    At the moment I let the SDS1104X-E warm up for it...

    I put a link to the siglent document that supports what I say, can you do the same, please

    250 µV stdev is absolute limit (above which it is broken) for a 2CH model.

    For 4ch model, at 1mV/div spec is "better than 25,55 dB SNR". There is formula below how it is calculated..
    Which would be arround 150 µV stdev MAX. For it to be considered damaged....
    Real noise will be half or better than that.

    Martin posted real measurements from the scope...



    "Just hard work is not enough - it must be applied sensibly."
    Dr. Richard W. Hamming
     

    Offline Performa01

    • Super Contributor
    • ***
    • Posts: 1729
    • Country: at
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #87 on: August 20, 2023, 08:56:03 am »
    The noise of a DSO has been debated at all times and one of the earliest occasions where the Siglent SDS1104X-E has been looked at has been back in February 2018, when our fellow "Master of Noise", @maxwell3e10, had a look at the cheapest 12 bit scope, an Owon XDS3062A:

    https://www.eevblog.com/forum/testgear/owon-xds3062a-input-noise-(good)-and-glitches-(bad)/msg1429292/#msg1429292

    He posted a table showing the noise levels of all the scopes he had tested at that time and unsurprisingly the 12bit Owon won - particularly at lower sensitivities, where the granular ADC noise is the main contribution to the total noise.

    You can see Tektronix being the king of noise, but also that a 12 bit ADC can be not much more than a marketing gag, if it is not properly calibrated and has high nonlinearities (take a close look at the 2nd screenshot in that post).

    My measurements back then, including noise spectra:

    https://www.eevblog.com/forum/testgear/owon-xds3062a-input-noise-(good)-and-glitches-(bad)/msg1432960/#msg1432960

    Here we got an updated table (shortened version, quite obviously, nobody wanted to see the noisy Tek anymore):

    https://www.eevblog.com/forum/testgear/owon-xds3062a-input-noise-(good)-and-glitches-(bad)/msg1433124/#msg1433124

    And finally the spectral noise density for full BW as well as 20 MHz bandwidth:

    https://www.eevblog.com/forum/testgear/owon-xds3062a-input-noise-(good)-and-glitches-(bad)/msg1433850/#msg1433850

    EDIT: Oh - and have you noticed how nobody wanted to share data of the Rigol 1054Z, even though it was the most popular scope at that time? I guess I know the reason why... ;)
    « Last Edit: August 20, 2023, 09:04:15 am by Performa01 »
     

    Offline MarioBros69

    • Contributor
    • Posts: 25
    • Country: es
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #88 on: August 20, 2023, 11:05:49 am »
    From someone with very little knowledge on these issues..., is the Siglent SDS1104X-E better than the Siglent SDS2202X-E 200MHz?
    There is very little difference in price, but which one is more worth it?
     

    Online tautech

    • Super Contributor
    • ***
    • Posts: 29810
    • Country: nz
    • Taupaki Technologies Ltd. Siglent Distributor NZ.
      • Taupaki Technologies Ltd.
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #89 on: August 20, 2023, 11:10:17 am »
    From someone with very little knowledge on these issues..., is the Siglent SDS1104X-E better than the Siglent SDS2202X-E 200MHz?
    There is very little difference in price, but which one is more worth it?
    If you need the BW SDS2202X-E everyday as it is a 350 MHz design.
    Very similar feature set to SDS1104X-E however the 4ch model offers more total capability if BW is not a concern.
    Avid Rabid Hobbyist.
    Some stuff seen @ Siglent HQ cannot be shared.
     

    Offline MarioBros69

    • Contributor
    • Posts: 25
    • Country: es
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #90 on: August 20, 2023, 02:18:38 pm »
    From someone with very little knowledge on these issues..., is the Siglent SDS1104X-E better than the Siglent SDS2202X-E 200MHz?
    There is very little difference in price, but which one is more worth it?
    If you need the BW SDS2202X-E everyday as it is a 350 MHz design.
    Very similar feature set to SDS1104X-E however the 4ch model offers more total capability if BW is not a concern.

    And about what is discussed in this thread, about noise, are the two the same?

    Are both models hackable?

     

    Offline MarioBros69

    • Contributor
    • Posts: 25
    • Country: es
    Re: buy a better oscilloscope than the Siglent SDS1104X-E
    « Reply #91 on: August 22, 2023, 09:22:37 am »
    Here is one quite old image. At this time I own one Rigol 1074Z (mod to 1104Z)
    In upper part of image (Rigol) there is also note about data used to measurements, today we know more also about this and it really use very extremely tiny intermediate buffer for measurements when Siglent use full acquisition data.

    And then bottom part of image Siglent SDS1104X-E. Settings as same as possible what was used with Rigol for fair compare.
    1mV/dif used because Rigol did not have 500uV/div. (also 1mV/div in Rigol is not true full resolution, it is some kind of production from 5mV/div)
    Around 60uV AC RMS (Stdev) is quite good for 100+ MHz bandwidth with 1Mohm inputs.
    Typically it is much better than service manual "go to repair" limit.

    This is many years old..
    Also I have measured several SDS1104X-E and I really can say that common value at 500uV/div is between 50 - 65uV/div  Stdev (AC RMS)




    Because the rigol shows the signal much thicker if the two are at 1mV/div?

    Edit: Sorry..., I thought the same signal was being measured in both

    « Last Edit: August 22, 2023, 09:38:02 am by MarioBros69 »
     


    Share me

    Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
    Smf