VERY BASIC Agilent MSO-X 2024a Question - Page 1
Forum section: electronics / testgear

author: jstarr
author_rank: Regular Contributor
timestamp: May 12, 2013, 11:59:43 pm
content: I am a ham radio hobbyist and restore old radios and related audio and RF circuits mainly < 150 Mhz. I have only used older analog scopes with plug-in modules like the Tek 7000 series and for the past 2 years a nice Rigol MSO model DS1102D. As I am moving into microprocessor controlcircuits on modern radios, I splurged and bought a Certiprime MSOX2024A. I was very surprised to find that I cannot figure out how to set this scope up for one of my most basic needs, i.e., looking at 3 independent simple sine signals at very different frequencies, typically out of phase with eachother, at the same time. I cannot for the life of me figure out how to set up individual triggers for each so I can have the scope in Run and see all three waveforms simultaneously. I can set the scope to trigger on one channel at a time only while the other channel signals are a blur. The scope trigger control only allows one channel to be selected at any time. Furthermore, on the very inexpensive Rigol MSO, I could easily set two different time base settings, e.g. 10ns and 50us for two channels, with different trigger for each channel and display both channels simultaneously. How can such a sophisticated scope as the MSOX2024 not provide the same basic feature as the Rigol 1102? I hope I am just not doing something right and I feel incredibly stupid even after reading the manual. Can some one offer me some basic advice please?thanksj

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 13, 2013, 01:24:10 am
content: Bad news. MSOX2024A has no alternate trigger. There is no way to watch 2 waveforms at different time base settings.

author: c4757p
author_rank: Super Contributor
timestamp: May 13, 2013, 01:26:48 am
content: Quote from: Hydrawerk on May 13, 2013, 01:24:10 amReally? I suddenly don't want it anymore.

author: skipjackrc4
author_rank: Regular Contributor
timestamp: May 13, 2013, 01:45:44 am
content: Quote from: c4757p on May 13, 2013, 01:26:48 amAgreed. I was thinking about buying one in a year, but without this feature, I'll be going for a Rigol, I suppose.

author: jstarr
author_rank: Regular Contributor
timestamp: May 13, 2013, 02:03:05 am
content: What would be the best DSO/MSO scope in the MSOX2024a pricerange that has individual triggers for each channel, at least two channels?j

author: Unknown
author_rank: Unknown
timestamp: May 13, 2013, 02:42:57 am
content: Dual time base is not a standard feature. The 7000 series needed either two horizontal plugins or a special dual time base plugin (eg. 7B53). Many portable scopes had a delayed trigger, but no alternate trigger. I believe the popular 465 fell in this category. I'm not aware of any quad-timebase DSOs. Alternate trigger will usually only trigger on two channels, even on four channel scopes. Triggering on multiple signals of different frequency is not something I've often needed. The workaround that you probably already discovered is single shot mode (assuming the frequencies are at least somewhat close). W2AEW has made a video about this on both a digital scope and an analog scope with dual time base.

author: c4757p
author_rank: Super Contributor
timestamp: May 13, 2013, 02:56:41 am
content: Dual time basewasnot a standard feature back when the 7000 series came out, and yet it was still capable with plugins. There is simply no excuse for it to be lacking in 2013. The fact that you don't often need it is not important - oscilloscopes are already packed to the gills with features that only get used once in a while, and it's really nice to have on that rare occasion when you do need it.

author: Unknown
author_rank: Unknown
timestamp: May 13, 2013, 03:07:14 am
content: Depending on how the trigger circuit is implemented, it may require a significant amount of extra hardware (trigger signal conditioning, trigger comparator and time base), unlike many software options that they can implement for 'free'. This was the reason why it was not common fifteen years ago. If it's an important feature for you, you should check the data sheet and manual before buying.

author: jstarr
author_rank: Regular Contributor
timestamp: May 13, 2013, 03:27:03 am
content: Is it just an alternating trigger mechanism or do you also need two time bases? Sounds like my old Rigol DS1102D was a winner where I could have Ch1 set for 10ns/ and the Ch2 at 500ms and I could trigger individually to see both signals simultaneously. Does anyone know if the newer Rigol DS2000 have the same feature? I read the DS4000 manual and it sounds like it lacks this feature.j

author: EV
author_rank: Frequent Contributor
timestamp: May 13, 2013, 04:48:41 am
content: Quote from: jstarr on May 13, 2013, 03:27:03 amRigol DS2000 has no alt trigger.

author: Rufus
author_rank: Super Contributor
timestamp: May 13, 2013, 12:23:06 pm
content: Quote from: jstarr on May 13, 2013, 03:27:03 amThe smarter the scope the more providing alternate trigger and dual time bases impacts the acquisition and display hardware. Someone here says there is no excuse for not providing the feature - that almost no one is providing the feature should give you a clue there is an excuse and the excuse is the value of the feature isn't worth the cost of implementing it. I think in the future you will be unlikely to find this feature except on the dumbest scopes where it doesn't cost much to implement and on money is no object top range models.On your Agilent you might try triggering on the slow signal and zoom to see the fast signal. You will see both waveforms in single shot. If you need a live display you could try setting a long trigger hold off to reduce the update rate. The fast signal won't be synced but the slow update should stop it just being a blur.

author: marmad
author_rank: Super Contributor
timestamp: May 14, 2013, 09:46:34 pm
content: Quote from: EV on May 13, 2013, 04:48:41 amAs mentioned here, the DS2000 has the Delay trigger - which can use an edge from each channel - thus providing a stable image for two unsynced waveforms. Although this wouldn't cover all situations where you might use an Alternate trigger, it will work in many cases.