MSOX-2000 Owners - Does your scope have this problem #1? - Page 1
Forum section: electronics / testgear

author: jstarr
author_rank: Regular Contributor
timestamp: May 14, 2013, 12:05:06 pm
content: I was looking at Dave's video on the Rigol DS2000 to show the effect of persistence and intensity of signal on the screen and tried to reproduce it on my MSOX2024. Either with the WavGen option or an independent external source Set up for a 1 Mhz Sine wave with AM modulation of 100 hz and 100% modulation. Set scope for either 5ms or 2 ms - can you find a stable trigger lock? My MSOX2024 cannot and has quite a bit of jitter in RUN. You can try this also with 1Mhz sine and 1khz AM modulation and a horizontal of 500us or 200us and same thing - jitter and not a stable screen picture in RUN. IS this inherent problem or just my scope?j

author: Nermash
author_rank: Frequent Contributor
timestamp: May 14, 2013, 12:41:46 pm
content: Think a little about triggering... Don't blame the scope first

author: jstarr
author_rank: Regular Contributor
timestamp: May 14, 2013, 12:55:52 pm
content: I reproduced what Dave showed in his Rigol DS2000 video, I did not see any instability in the his vidoe on the DS2000 display. Identical conditions in MSOX2024 cannot get stable signal. Perhaps you can explain why the different behaviour between the two scopes? I can understand that at 0% modulation you may lose the trigger but then there should be a missed trigger event not a shift in the underlying heterodyne frequency. Is it a "feature" or a "problem"j

author: EV
author_rank: Frequent Contributor
timestamp: May 14, 2013, 01:14:41 pm
content: You must set trigger level and holdoff to a suitable value.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 14, 2013, 02:03:22 pm
content: In complex signals, never rely on theAutosetbutton.

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 14, 2013, 03:23:31 pm
content: Quote from: Hydrawerk on May 14, 2013, 02:03:22 pmTaking that a step further I never rely on the Autoset button AT ALL!

author: jstarr
author_rank: Regular Contributor
timestamp: May 14, 2013, 04:45:15 pm
content: I did NOTuse Auto but tried a variety of trigger settings, levels, holdoff/delays and no setting could provide a stable triggered signal under the conditions tested (same as Dave's in his DS2000video). I am not trying to bad-mouth the MSOX-2024 - I own it! I just want to find out if this is an intrinsic problem in the model or a problem only with my scope.Can anyone who owns a MSOX2000 try this PLEASE and provide feedback here?tiajohn

author: PA4TIM
author_rank: Super Contributor
timestamp: May 14, 2013, 05:02:04 pm
content: I have not seen that video so I probably am thinking the wrong way but just to be sure- you have no troubles triggering in normal use ? ( could it be something in the menu settings ? Just a wild guess. Something that is not a menu choise on the Rigol but is on the Agilent, so Dave does not show that setting ? like a friend with the same scope as me did not manage to get the same picture as me because a menu setting I had switched on and he had never used)- not to offend you but you are only human too ( I hope ;-) ) the trigger source is on the right channel ?Do you have a link to that video ? The Agilent is an other scope as the Rigol and I have a good DSO from Hameg ( 350 MHz) . If you have a link I will try the same thing on my Hameg and see if it does the same thing as Agilent or as the Rigol.

author: EV
author_rank: Frequent Contributor
timestamp: May 14, 2013, 05:09:05 pm
content: Here is 1 MHz sine modulated with 1 kHz. Holdoff is 800 us. Look at the picture.

author: AndyC_772
author_rank: Super Contributor
timestamp: May 14, 2013, 05:20:44 pm
content: Here's the signal you describe, with a perfectly stable trigger on my 3054A.The trick is to set the holdoff correctly. You want the scope to trigger when the waveform first crosses the trigger threshold, but then to not re-arm the trigger circuit again until after that particular AM cycle has decayed away. In this example, the amplitude of the AM signal exceeds the trigger level for a period of about 4ms per cycle, so by setting the holdoff to 5ms I ensure that when the scope has triggered once, it won't trigger again until the next cycle reaches the necessary amplitude.

author: jstarr
author_rank: Regular Contributor
timestamp: May 15, 2013, 02:18:06 am
content: Thanks EV and AndyC_772.This confirms my MSOX2024a needs servicing. I cannot get the display to stop the jittering even when setting my scope with holdoff as you describe... Holdoff seems to have no effect at any setting. I have one other problem in the Wavgen I want to post in a new topic to see if that needs repair as well.j

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 15, 2013, 05:27:59 am
content: Just setup the same wave on my MSOX2024A: 1Mhz Sine, 1Vp-p, AM Modulation, 100Hz Freq, 100% Depth outputted from an Agilent 33220A.Signal sits perfectly still once the trigger level was set at around 500mV for this example or about half way to the peak.

author: EEVblog
author_rank: Unknown
timestamp: May 15, 2013, 05:43:04 am
content: Quote from: jstarr on May 15, 2013, 02:18:06 amI find it hard to believe your scope is faulty in this respect. It is just very very unlikely.Are you absolutely sure you don't have anything else screwing up the triggering?Yes, like the others, it goes stable with about 500ns of holdoff and say level at 3/4 peak.

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 15, 2013, 05:49:42 am
content: Yes, like so:

author: EV
author_rank: Frequent Contributor
timestamp: May 15, 2013, 07:50:22 am
content: Quote from: jstarr on May 15, 2013, 02:18:06 amHave you set the tigger level also as in my picture?

author: jahonen
author_rank: Super Contributor
timestamp: May 15, 2013, 08:17:24 am
content: Perhaps you have trigger HF reject and/or noise reject turned on?Regards,Janne

author: Sander
author_rank: Contributor
timestamp: May 15, 2013, 04:34:22 pm
content: ben_r_ have you got the memup-option? I can't get it to use 10.0MSa/s, might be because I haven't got that option (yet...).Looks like this on my unit:

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 15, 2013, 05:14:29 pm
content: Quote from: Sander on May 15, 2013, 04:34:22 pmYes, I do have it.

author: EV
author_rank: Frequent Contributor
timestamp: May 15, 2013, 05:54:00 pm
content: Quote from: jstarr on May 15, 2013, 02:18:06 amPress the Single key. What do you get then? Attach a picture for us.

author: jstarr
author_rank: Regular Contributor
timestamp: May 15, 2013, 06:15:49 pm
content: EV, Ben_r_I am almost certain but will check again when I get home. BTW, what software/link are you using to get the nice colored screen shots? I have IntuiLink and it seems only to provide B&W. I guess I need the VGA/Lan adapter?thanksj

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 15, 2013, 06:21:35 pm
content: Quote from: jstarr on May 15, 2013, 06:15:49 pmI am using the Agilent VGA/LAN card. Gives you tablet control, VGA out, screen capture, browser control, and setup options. Pretty cool actually if you can get it for a good price.

author: EV
author_rank: Frequent Contributor
timestamp: May 15, 2013, 08:06:40 pm
content: Quote from: jstarr on May 15, 2013, 06:15:49 pmI don't have this scope, but it should be possile to save screen image with Save key. Look at your users manual.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 15, 2013, 08:19:20 pm
content: You can save the png printscreen to your USB flash disc by pressingSave/Recallor you can use theQuick Actionbutton. (After you configure it!)

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 15, 2013, 08:26:22 pm
content: Yea thats whats nice about having the VGA/LAN card in the Agilent scopes. All I have to do to get a screen shot is go to my computer, click the saved link to my scopes IP address and click the Get Image button on the first page and I have a screen shot ready to save. Super fast and convenient. If you need/want the feature its very nice to have.

author: EV
author_rank: Frequent Contributor
timestamp: May 16, 2013, 09:54:46 am
content: If you can not get the trigger work from CH1, you can at least do like I have done in the attached picture. There is 1 MHz sine wave modulated with 1 kHz sine wave in CH1. Scope is triggered from CH2 where is 1 kHz sine wave. Trigger position and holdoff value are not critical.

author: EEVblog
author_rank: Unknown
timestamp: May 16, 2013, 10:43:57 am
content: Have you reset all the defaults in the scope and tried it again?

author: jstarr
author_rank: Regular Contributor
timestamp: May 16, 2013, 02:31:01 pm
content: I am going to activate the Training Signal 30-day demo and see if i can reproduce the more complex trigger setting scenarios. I still think there is a trigger problem, but was advised by Agilent Tech Support to first duplicate the training demos and see if any do not behave as expected. will report back in a few days.j

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 16, 2013, 03:52:57 pm
content: Quote from: jstarr on May 16, 2013, 02:31:01 pmBy Training Signal demo do you mean the DSOXEDK Educators Kit?LINKI cant believe they try and get $500 for that AND the WaveGen. Guess you could get the two for $500 now as they are doing the buy one get one free promotion, but still... WAY overpriced.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 16, 2013, 07:44:13 pm
content: Yes, Agilent is quite overpriced but LeCroy is even worse. I would buy Rigol if they had a better firmware download support and a few another details... But DSOX2000 is now quite the only scope with a good built-in function generator... Yes, in 6 months Rigol will probably release their scopes with even better function generator, but...

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 17, 2013, 02:56:13 pm
content: Quote from: jstarr on May 14, 2013, 12:05:06 pmSo I tried it. The Autoset doesn't work as expected, but never mind! I set the Holdoff to 8ms and now the waveform is stable. My scope is OK.

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 17, 2013, 03:06:07 pm
content: Awesome!

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 17, 2013, 03:22:07 pm
content: Well, nothing special... But I wanted to try it...