Author Topic: REVIEW - Rigol MSO5000. Tests, bugs, questions  (Read 26596 times)

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Offline noreply

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #225 on: July 24, 2020, 09:58:16 pm »
Thanks for the nice 'explanation' it certainly makes sense.

Yeah, I remember the 'crisp and bright' Lissajous figures on the CRT

But those old CRT scopes - compared to the MSO5000 -  were true dinosaurs - not only big and heavy but not so clever at the same time  :P

BTW

I also came across a YT video from which I 'lifted a frame' - clearly showing that even an 'old' R&S scope is able to do better job with X-Y - it look much crispier than the Rigol - but at a much higher price.

I guess for my immediate needs - the use of the Rigol's X-Y is 'good enough' for me.

Perhaps someone could 'chime-in' with a screen shot from the Siglent 2104X Plus in X-Y mode with a spinning circle?

I'm thinking it will be same as Rigol   ;)
« Last Edit: July 25, 2020, 01:01:57 am by noreply »
 

Online tautech

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #226 on: July 25, 2020, 02:12:20 am »

Perhaps someone could 'chime-in' with a screen shot from the Siglent 2104X Plus in X-Y mode with a spinning circle?

Nice video of a pre-release unit doing X-Y for you to download here:
https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg2787208/#msg2787208
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Offline noreply

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #227 on: July 25, 2020, 03:45:00 am »

Perhaps someone could 'chime-in' with a screen shot from the Siglent 2104X Plus in X-Y mode with a spinning circle?

Nice video of a pre-release unit doing X-Y for you to download here:
https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg2787208/#msg2787208


Interesting...

That was back in 2919

Any chance of getting a 2000x Plus and doing the following;-

Get a 10MHz Sine 500mv signal - out of the AWG on the 2000x and connect to CH1 on the 2000x

Get another 10MHz Sine 500mv signal - from another source and connect to CH2 on the 2000x

Then select X-Y mode on the 2000x

You should see a circle

If the circle is not moving - the two 10MHz frequency sources should be 'in sync'

Take a screen shot and post here

Thank You :-+

Its probably unlikely that the circle is perfectly 'still' and not moving - because the respective independent 10Mhz clocks will be drifting.

If CH1 source is from a GPSDO - stabilized and locked to GPS signal - you should have (if you have a well disciplined clock) at least 10E-12 accuracy.

That's 0.000001Hz  accuracy  :popcorn:

Now you can use this 10MHz signal to calibrate all the other equipment in the lab  ;)

Get your other 10MHz signal - from the device being calibrated is connected and connect to CH2 on the 2000x

Put 2000x in X-Y mode

Circle will most likely be spinning.

Adjust the frequency on the source connected to CH2 (the device you are calibrating) - until the circle is virtually frozen i.e not moving.

Unfortunately the circle will still be moving very slightly.

Write down the frequency shown on the source connected to CH2

Note the last significant digit.

It should be at least 0.01Hz - if you have a good frequency source.

Now look at the circle and get a stop watch.

Start the stopwatch and time 'in seconds' - how long it takes for the circle to rotate 2 times.

The circle actually rotates 360 degrees - because we see it in 2D on the 2000x screen - we need to have 2 x 180 degree spins.

Write down the number of seconds and now divide 1 by the number of seconds.

Hopefully you will get a small fraction - something like 0.004567 - as an example.

Now you can ADD this number to the least significant figures you recorded earlier for frequency of CH2 source.

For example if the least significant figures were  0.01Hz - then adding 0.004567 will yield 0.014567 Hz

Now you will have CH2 calibrated to 'atomic time' accuracy and the frequency will be 10.000 000 014567 Hz

Hope the above procedure is useful for anyone wanting to calibrate CH2 frequency to the CH1 reference (as used in the above example  :)





 

Offline Gandalf_Sr

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #228 on: July 25, 2020, 09:22:28 am »
Kehall,

If the sellers of the scope won't refund your money and you paid with a credit card, or even a debit card that has a VISA or MC logo on it, you can use that to get sorted out.  Call your card company and simply tell them that you purchased with their card and the vendor won't refund for a defective item that's been back several times for repair and ask them to raise a claim; they will probably put you onto VISA or MC.

If you pursue this avenue, you may well end up with a refund without having to return the scope.

In the UK there is also buyer protection law that says that an item sold has to be of "merchantable quality" meaning it has to perform the designed function properly.

I like my MSO5000 but the first one I got was hw 1.0 after I'd specifically stated that I wanted a new unit on my order through Tequipment.net.  They (Tequipment.net) got be a brand new scope (hw vn 1.1) and sent me a free shipping RMA for the return of the first one.

Good luck.
If at first you don't succeed, get a bigger hammer
 
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Offline kehall

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #229 on: July 25, 2020, 10:39:06 am »
Kehall,

If the sellers of the scope won't refund your money and you paid with a credit card, or even a debit card that has a VISA or MC logo on it, you can use that to get sorted out.  Call your card company and simply tell them that you purchased with their card and the vendor won't refund for a defective item that's been back several times for repair and ask them to raise a claim; they will probably put you onto VISA or MC.

If you pursue this avenue, you may well end up with a refund without having to return the scope.

In the UK there is also buyer protection law that says that an item sold has to be of "merchantable quality" meaning it has to perform the designed function properly.

I like my MSO5000 but the first one I got was hw 1.0 after I'd specifically stated that I wanted a new unit on my order through Tequipment.net.  They (Tequipment.net) got be a brand new scope (hw vn 1.1) and sent me a free shipping RMA for the return of the first one.

Good luck.
Thanks, the refund has been offered and the dealer is not being an issue, the new scope they will supply has overshoots though and the service centre isn't really believing it isn't 'normal' as unfortunately the other scopes they have had the same problem and they're not speaking the right people at the R&D/factory as they claim to know nothing about the 'lfcal.hex' file :-DD

Hence the poll I created to help evidence the fact that it is NOT normal and they need to get to the bottom of it...

Do me a favour please and lodge your 'vote' here :) https://www.eevblog.com/forum/testgear/rigol-mso-5000-overshoot-or-not-overshoot/

I'm happy with the scope if I can get a good one, but that's the problem, I have the worst luck when it comes to things like this so even the brand new 'factory fresh' replacement they offered is 'bad'...
 

Offline jemangedeslolos

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #230 on: August 13, 2020, 05:46:53 pm »
Hello,

Has anyone ever tried to loop TRIG OUT to EXT TRIG?

I tried this to engage the totalizer on EXT TRIG but it doesn't work.
I checked my TRIG OUT signal and it's OK.
I checked my EXT TRIG input and the totalizer function with my AWG and it's OK.
I checked my cable and it's OK.

The only thing I haven't checked is the TRIG OUT signal level.

Any ideas ?  (I have a MSO7000 but I guess the implementation is the same )

Thank you  :)
 

Offline Testtech

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #231 on: August 13, 2020, 08:38:40 pm »
UPDATE:

Thanks for the input, I am aware of you points, I tried 3 other signal sources with the same result.
I contacted Rigol Tech Support, and after discussion, an RMA was issued and the instrument shipped back today for replacement.

I will advise when the replacement arrives.

Greetings,

I have encountered an issue with my MSO5204 where a high frequency sinewave shows what I am calling artifacts, for lack of a better term.
Please see the pictures.
The "artifacts" can be changed by slightly varying the frequency, or can be made to disappear by turning on another channel. Also, changing the depth from AUTO to a much higher value will seem to make it disappear. It is apparent without the Color Grading on, but is easier to see in Color Graded mode.
These are most easily seen at higher frequency, and yes, I have tried several other sine sources, and all present the same.

Has anyone else encountered this? Perhaps someone can try this with their instrument and see if it does something similar
« Last Edit: August 13, 2020, 11:03:41 pm by Testtech »
 

Offline noreply

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #232 on: August 13, 2020, 09:24:59 pm »
Greetings,
I have encountered an issue with my MSO5204 where a high frequency sinewave shows what I am calling artifacts, for lack of a better term.

Sure ... happy to check this out for you  :)

BUT

Before you go any further - can you please provide more details on your high frequency sinewave like ;-

1. What is the source of the sinewave
2. Have you checked the signal - is it clean?
3. Perhaps your source has the mysterious 'artifacts'


If you have a 'dodgy' source signal - the MSO will be doing its 'job' to detect the 'artifacts'

By varying the source frequency - and the artifacts disappear is a good clue that the source is generating the 'artifacts'

By changing input channels (depending on which one you use)

- this also will / may reduce the MSO's sampling rate

- hence the 'artifacts' disappear

- from your 'plots' this CAN BE CONFIRMED

- because CH2 has reduced sampling (shares ADC) and CH3 is same as CH1

- so its expected to 'see' the 'artifacts' on CH1 AND CH3 - if its really there - but not on CH2 - so your MSO is behaving as expected



You need to get a verified and 'clean' Source to do MSO waveform 'artifacts' debugging - otherwise the MSO might be doing its 'job' and reporting the 'artifacts' because they are really there  :popcorn:


If you are still having problems after checking your sine source

- then please give me your EXACT MSO parameters you used for your measurement (best way is to press the 'default' button first - then record all the settings you make)

- also the sine source frequency / amplitude
 

Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #233 on: August 13, 2020, 10:05:41 pm »
Greetings All,
I received my replacement MSO5074 this week and updated to the latest firmware, calibrated, etc.. Here are some new measurements. As before (see my post on page 8 ) all four probes are at 1X and connected to AWG I output (set to 100kHz and 5Vp-p). As can be seen, the four channels are much closer in agreement than with my first scope. This is a big improvement. Interestingly though, they are not quite the same at the 200nS area. Ch1 and Ch4 are in very close agreement so they may have to be my go-to channels. This, I suppose, is what $1k buys and I should accept it and move on. Any thoughts?
 

Offline noreply

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #234 on: August 13, 2020, 10:40:48 pm »
@Pulsepowerguy

First of all - hope that your new MSO meets your expectations  :)

Please don't dismiss the capabilities of this nice bit of 'kit' - even if its in the $1K range - it will blow much higher priced devices out of the water.

My first suggestion to you is to do your testing again - but this time - see if you can 'borrow' some 500MHz 'expensive' probes.

My gut feeling is that the current problems you are having are related to your probes rather than the MSO itself.

The MSO can handle without problems 400MHZ+ which is great.

The supplied probes are rated to 350MHZ - but these are 'cheap' probes - mainly intended for low frequency work - despite their rating.

There are significant 'clues' in your plots that - at least at 1st step in your quest to get the response you are expecting - indicating potential probe issues.

The rising edges and trailing on your plots seem to be fine and are all 'in tune' with each other.

Your problems appear with the 'overshoots' - an area which closely correlates to probes and their inherent ability to handle these signals.

So, before you start to  |O - just try things out with the 'best' highest specification probes you can get your hands on and see how the MSO behaves

After checking out your probes, if you are still having identical issues - we can then try to see what might be causing this   :)

BTW

A quick test (but not 100% conclusive) is to switch probes with the different channels - and see if the plots 'follow the probes' - if it does that's a big clue  ;)
« Last Edit: August 13, 2020, 11:11:04 pm by noreply »
 

Offline Howardlong

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #235 on: August 13, 2020, 11:20:19 pm »
Greetings All,
I received my replacement MSO5074 this week and updated to the latest firmware, calibrated, etc.. Here are some new measurements. As before (see my post on page 8 ) all four probes are at 1X and connected to AWG I output (set to 100kHz and 5Vp-p). As can be seen, the four channels are much closer in agreement than with my first scope. This is a big improvement. Interestingly though, they are not quite the same at the 200nS area. Ch1 and Ch4 are in very close agreement so they may have to be my go-to channels. This, I suppose, is what $1k buys and I should accept it and move on. Any thoughts?

 

Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #236 on: August 13, 2020, 11:53:05 pm »
@Pulsepowerguy

A quick test (but not 100% conclusive) is to switch probes with the different channels - and see if the plots 'follow the probes' - if it does that's a big clue  ;)

Sorry. I neglected to mention that I swapped the probes every which way and nothing changes, so the probes are not the issue as far as channel to channel differences go.

I really like many things about the scope - this one is definitely better than the last one - I just get the impression that this is the best it gets for the money. I have been a Tek user for my entire 40 year engineering career and I never thought I could afford a decent scope for my home. From what I can tell on this forum, the factory calibration of this scope has a degree of variability from unit to unit (and from channel to channel in my sample of two machines). That is a pity, as I would go to great lengths to tune this thing if I could.
 

Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #237 on: August 14, 2020, 01:02:43 am »
Well, well. I happen to have a Probemaster 500Mhz probe and a Tek P6139B. Below are all three (one at a time, plugged directly into AWG I) - all three were tuned for the scope and note that the Rigol probe is now at 10X. Interesting how the Rigol has the least overshoot, and the Probemaster the greatest. These overshoots are not tunable as the trimming cap only affects the relatively long time behavior. I kinda like the Tek probe's behavior the best.

All of these traces look a lot cleaner because I no longer am trying to compare channels so the connection to the generator is very short.
 

Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #238 on: August 14, 2020, 01:05:27 am »
...and here are the same three probes looking at the same output, but plugged into a TEK DPO3034 (all probes re-tuned for it). Interesting.
 

Offline noreply

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #239 on: August 14, 2020, 01:06:32 am »
... all four probes are at 1X ...

Like I said - your MAIN problem is in the probes - see video Dave made (thanks @Howardlong) posted above.

Swapping probes as suggested and like you did only confirms that ALL probes exhibit identical behavior - it is not conclusive that your problem is not probe related.



First of all CH1 and CH4 - your best channels are using different ADC's as the MSO has 2 of these shared between the 4 channels.

CH1 and CH2 if used simultaneously will be lower sampling hence BW capability than if you used CH1 and CH3 or CH2 and CH4 - in effect to have a dedicated ADC per channel.



So don't expect to have SAME performance across ALL channels at the same time when pushing the BW / sampling rate.


It would still be very interesting - if you are able to get hold of much better probes which are rated WELL ABOVE the MSO specifications - I suspect you will get a much better response.

For now - try to run the test again but compare only CH1 to CH3 OR CH2 to CH4 - set your probes to x10 when you do this - see what happens ?

*** If you can try a direct coax connection to CH1 from sig gen and to CH3 from sig gen and compare this - make sure the COAX is appropriately terminated.

EDIT:

SORRY - I think our posts crossed
« Last Edit: August 14, 2020, 01:12:13 am by noreply »
 
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Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #240 on: August 14, 2020, 01:37:22 am »
Here are the two scopes looking at AWG I with a bit of coax - no probes. ARgh! I noticed that the tek bandwidth was set to 20MHz for the previous captures.  :palm: This time it is set to full (350MHz). Also, I don't have a terminator for the Rigol scope so left the TEK input at 1Meg. Take that into account.

NOREPLY: I do not agree that the sharing of the digitizers is involved here. I maintain that this is a "front end" issue, where each channel's signal conditioning is noticeably different. I turned off all but one channel and the response was indiscernible from that with all four channels active.

I would really like to see the behavior of the 350MHz version of this scope.
« Last Edit: August 14, 2020, 01:45:19 am by Pulsepowerguy »
 

Offline noreply

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #241 on: August 14, 2020, 03:29:08 am »
@Pulsepowerguy

Thanks for your feedback :)

Also for doing some more testing.

I did notice that your source frequency was set to 100KHz - if this is still the case than the ADC sampling should not be an issue.

My comment(s) about the channels and the 2 ADC shared between 4  channels was just to alert you (just in case you were not) that all channels are NOT identical with regard to sampling - and calibration - as you most likely know now.

I am happy to 'run' your tests on my MSO - which has been enhanced to 350MHz

PLEASE let me know your exact settings - AFTER you perform a reset to the default settings (press the default button) and them let me know precisely what settings you make - step by step - including your AWG setup.

I will reproduce this - and we will see how the two MSO's compare.

Its really late here in London - so I need to get some  :=\ just now.

I wanted to quickly post this message - so you can let me know your setup - this way when you are catching some  :=\ , i'll run the tests  :popcorn:

Take Care for now  :)
 
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Offline jemangedeslolos

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #242 on: August 14, 2020, 06:56:02 am »
Hello,

Has anyone ever tried to loop TRIG OUT to EXT TRIG?

I tried this to engage the totalizer on EXT TRIG but it doesn't work.
I checked my TRIG OUT signal and it's OK.
I checked my EXT TRIG input and the totalizer function with my AWG and it's OK.
I checked my cable and it's OK.

The only thing I haven't checked is the TRIG OUT signal level.

Any ideas ?  (I have a MSO7000 but I guess the implementation is the same )

Thank you  :)

Just checked and there is no EXT TRIG input on the MSO5000  >:D   :palm:
I will try on the MSO7000 desert topic !
 

Offline Howardlong

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #243 on: August 14, 2020, 01:31:15 pm »
Here are the two scopes looking at AWG I with a bit of coax - no probes. ARgh! I noticed that the tek bandwidth was set to 20MHz for the previous captures.  :palm: This time it is set to full (350MHz). Also, I don't have a terminator for the Rigol scope so left the TEK input at 1Meg. Take that into account.

NOREPLY: I do not agree that the sharing of the digitizers is involved here. I maintain that this is a "front end" issue, where each channel's signal conditioning is noticeably different. I turned off all but one channel and the response was indiscernible from that with all four channels active.

I would really like to see the behavior of the 350MHz version of this scope.

Sorry if this has been mentioned before, but are you sure you're not over driving the channel inputs? a lot of the trace isn't displayed.

If it's a Hi-Z input that leaves the source unterminated. I'm not sure you can draw many conclusions from that.

I'm now not sure what it is you're trying to show?

If it's that the channels behave differently when you're over driving them or not terminating the source, then I'm not sure now what the complaint is?
 

Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #244 on: August 14, 2020, 03:07:01 pm »
Quote from: Howardlong on Today at 01:31:15 pm

If it's that the channels behave differently when you're over driving them or not terminating the source, then I'm not sure now what the complaint is?


I agree with you on several points - over driving the inputs eventually leads to problems, but there is a level at which the signal can exceed the vertical boundaries without distortion and that can be discerned by switching the range while looking at the response. Both the Rigol and the Tek scopes appear to be working well with a setting of 100mV/div and 2.5V offset to look at a 5Vp-p square wave (but of course I could be mistaken). The source really should be terminated at 50 \$\Omega\$ , so my measurements have the nasty spike on the leading edge (I have no termintator at home, but will work on that). Still the comparison seems valid.

My concern has been with the variance from channel to channel, and this newer scope is much much better than the first one I received. I guess you could say that I am in the validation phase of the purchase - I am coming to terms with the behavior of this scope while learning of its limitations. It is definitely a good piece of gear for the price.

Update: I wised up and added two, 100 Ohm, 1/4W resistors to the end of my bit of coax (shortest possible connection for low inductance) and reconnected all of the Rigol Probes (set to 10X) to the resistors. See attached. The match up is, in fact, better looking now.  :-+
I appreciate everyone's feedback BTW.  :clap:

@noreply, I would still like to see your results. Please don't stay up so late just for this though.  ;)
« Last Edit: August 14, 2020, 08:55:47 pm by Pulsepowerguy »
 

Offline noreply

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #245 on: August 16, 2020, 03:05:13 pm »
@noreply, I would still like to see your results. Please don't stay up so late just for this though.  ;)

Please provide EXACT MSO configuration / settings - so I can reproduce SAME conditions here & do the testing.



 
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Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #246 on: August 16, 2020, 05:08:55 pm »
@noreply I think the attached setup file will work. After loading it myself I had to activate AWG I, but it then duplicated my setup exactly.
The external setup is:
~8" coax with BNC on one end (connected to AWG I) while the other end is terminated with 2, 100 Ohm resistors (shortest possible leads). Ch1 is connected to these resistors with a very short (imperfect, I know) BNC to alligator clip adapter. Ch2 is a TEK probe, Ch3 is a Rigol probe, and Ch4 is a ProbeMaster probe. The photo shows this mess.
 

Offline Howardlong

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #247 on: August 16, 2020, 05:53:33 pm »
I'm probably being a bit thick here.

I loaded up your setup file.

As discussed previously, the channels are being overdriven, 3Vpp on 100mV/div

There are now four different probing arrangements, one on each channel, so I'm not sure how you're demonstrating that each channel is different?


What is true is that this scope has a very, very noisy front end!
 
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Offline Pulsepowerguy

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #248 on: August 16, 2020, 06:33:22 pm »
Quote from: Howardlong on Today at 05:53:33 pm
I'm probably being a bit thick here.

I loaded up your setup file.

As discussed previously, the channels are being overdriven, 3Vpp on 100mV/div

There are now four different probing arrangements, one on each channel, so I'm not sure how you're demonstrating that each channel is different?


What is true is that this scope has a very, very noisy front end!

You are certainly not being thick.  :) Someone suggested that the Rigol probes were responsible for the odd responses I was seeing, and I am 'shifting gears' by attempting to show here that the different probes look very similar to each other (though not identical) on this scope whereas the direct connection to Ch1 looks pretty flat. These same probes look different from this on the TEK scope (see attached). Its a bit odd. What is it about the front end of this scope that causes the 10X probes to interact differently than direct (tied to 50 ohms) connection. The TEK scope traces for the same conditions (re-tuned the probes of course) do look different from each other, but none of them exhibit the ripple that shows up on the Rigol.

I do not see any evidence of overdrive with this setup though. What am I missing? Many modern scopes must deal with this kind of signal and do it well. The Tek scope shows no problems with this either. That being said, the older scopes (20th century) I have used do not do so well. I do know that the direct connection (1X) will be over driven at one setting more sensitive than what I stored. I must reiterate that this particular scopes is behaving much much better than my first one and I am very happy with it now. I do look forward to seeing the behaviour of the 350MHz version for comparison.

Your comment about the noisy front end is interesting - what scope(s) are you comparing to?
« Last Edit: August 16, 2020, 06:51:54 pm by Pulsepowerguy »
 

Offline Howardlong

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Re: REVIEW - Rigol MSO5000. Tests, bugs, questions
« Reply #249 on: August 17, 2020, 01:56:28 pm »

You are certainly not being thick.  :) Someone suggested that the Rigol probes were responsible for the odd responses I was seeing, and I am 'shifting gears' by attempting to show here that the different probes look very similar to each other (though not identical) on this scope whereas the direct connection to Ch1 looks pretty flat. These same probes look different from this on the TEK scope (see attached). Its a bit odd. What is it about the front end of this scope that causes the 10X probes to interact differently than direct (tied to 50 ohms) connection. The TEK scope traces for the same conditions (re-tuned the probes of course) do look different from each other, but none of them exhibit the ripple that shows up on the Rigol.

I do not see any evidence of overdrive with this setup though. What am I missing? Many modern scopes must deal with this kind of signal and do it well. The Tek scope shows no problems with this either. That being said, the older scopes (20th century) I have used do not do so well. I do know that the direct connection (1X) will be over driven at one setting more sensitive than what I stored. I must reiterate that this particular scopes is behaving much much better than my first one and I am very happy with it now. I do look forward to seeing the behaviour of the 350MHz version for comparison.

Running a scope channel outside of the graticule, i.e., overdriving, isn't typically a recommended use case because the preamps in the front end will typically be in saturation, and will have a recovery time and usually uncharacterised behaviour while coming out of saturation. There is a frankly weird video that Rigol put up supposedly demonstrating their high resolution mode that seems to suggest the Rigol will operate without problems with channels well outside the graticule, but it doesn't seem to demonstrate high resolution mode at all. What's not clear from this is what the limits and behaviour of the scope channels are if overdriven, for example recovery time.



Quote

Your comment about the noisy front end is interesting - what scope(s) are you comparing to?

I did some measurements about a week or so ago to derive the effective bit resolution. The MSO5000 typically had around a ~10dB worse noise floor (a bit less than a 2 bit deficit on average).

Tests were done in all cases with:

o 20MHz channel bandwidth
o 1us/div
o 1MSa memory depth (or as close as possible)
o 8 bit
o 1M ohm channel, with 50 ohm terminator attached

[attachimg=1]
 
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