EEVblog
Vložit
- čas přidán 5. 08. 2019
- Most modern DSO's don't have Alternate Triggering, but Dave shows you how to do it anyway!
This allows you to trigger on, align, view and anaylse two otherwise asynchronous time un-correlated signals on the screen at once.
Also a look at Dual Time Base oscilloscopes.
Oscilloscope Tutorial Video Playlist: • Oscilloscope Tutorials
Forum: www.eevblog.com/forum/blog/ee...
#Oscilloscope #Trigger #Tutorial
Bitcoin Donations: 38y7DE8HEHNj8fGDtUr4PkCn9nWxiorvvy
Litecoin: ML7oQokTwB38bgzzjLDbRV97HKAHuwRfHA
Ethereum: 0x11AceA38DCA9DbFfB4F35f3F746af65F9dED28ce
EEVblog Main Web Site: www.eevblog.com
The 2nd EEVblog Channel: / eevblog2
Support the EEVblog through Patreon!
/ eevblog
AliExpress Affiliate: s.click.aliexpress.com/e/c2LRpe8g
Buy anything through that link and Dave gets a commission at no cost to you.
Stuff I recommend:
kit.com/EEVblog/
Donate With Bitcoin & Other Crypto Currencies!
www.eevblog.com/crypto-currency/
T-Shirts: teespring.com/stores/eevblog
Likecoin - Coins for Likes: likecoin.pro/@eevblog/dil9/hcq3 - Věda a technologie
Arduino Sketch to test this:
void setup() {
pinMode(LED_BUILTIN, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
}
void loop() {
digitalWrite(LED_BUILTIN, HIGH);
for (uint8_t i = 0; i < 50; i++) {
digitalWrite(7, HIGH);
delayMicroseconds(1);
digitalWrite(7, LOW);
delayMicroseconds(1);
}
delay(10);
digitalWrite(LED_BUILTIN, LOW);
for (uint8_t i = 0; i < 50; i++) {
digitalWrite(8, HIGH);
delayMicroseconds(1);
digitalWrite(8, LOW);
delayMicroseconds(1);
}
delay(10);
}
Ha. Nice one. Not often is code posted in the comments.
Nice!
thanks, it works :)
You can't have more than one edge trigger in a pattern because two edge triggers cannot occur at the same time. This is by definition, because an edge trigger occurs at a single point in time, which in theory is infinitly small.
Hope this makes sense.
Of course, makes sense now, i should have realised that.
The hardware probably has just one edge detection circuit.
@@donreid358 Even if it did, then it still does not make sense to use two edge triggers in a trigger pattern.
@@marknn3: yes I see what you are saying and agree. An edge happens at a narrow instant in time and 2 won't likely be at the same instant.
Yes but for OR why do they need to happen at the same time? If it was AND it would make sense they can't both be edges but you can certainly OR the outputs of two edge detectors if they produce a pulse for an edge.
Enjoying these tips and tricks Mr Jones, working my way through your playlist.
Thanks for sharing and best regards from the UK.
For a scope without this feature but with the ability to save a reference waveform (eg the Rigol DS 1054Z without options enabled) you can zoom in appropriately, trigger off one channel, and save that as a reference. Then trigger off the second channel and compare with your reference.
Have done this many times!
I have an old crappy gratten 100mhz 2 channel scope with a properly named alternate trigger ... it has proven to be very useful
How timely! I just encountered this over the weekend. I reconnected my bench setup and tried again on my Rigol DS2302A-S and got it to work with pattern triggering. Thanks for the tip!
FWIW, I'm looking at the time delay from externally triggering a bank of HP 3478A DMM's until I get the "voltmeter complete" pulse from the rear BNC connector. Verifying that all 4 meters are triggering in sync.
Some older dual timebase analog scopes had a mode like that. It alternated between timebase A and B. You couldn't do "delayed" mode with it but in many cases just the A,B toggle effect was all that was needed.
You could also do the "overlapped" mode on the delayed time base. This could be even better if you wanted to measure the time between the two events as well as see what the later one looked like in detail.
I laughed out loud; "... Bloody touch screens..."
Never noticed Dave's logo on the scope until today ;)
Thanks DJ. Love a good scope tute.
For the Rohde&Schwarz I use high for the first channel and low for the second, then I get a stable trigger.
Thanks for this great hint.
Greetings,
Wolfgang
In analog days, you could TRY composite trigger, combined with variable hold-off amend MAYBE get the two bursts to align. In 7000 series you could use Alternate - alternate mode and pair channel one display and trigger to time base A and channel 2 display and trigger to time base B. Pretty slick.
Weird my old Tektronix TDS3000 has alternate triggering, I just assumed other nice DSO's had it also.
I was literally trying to do this last night, great video!
I like the 2016 special edition faceplate for the nobs and buttons. ;-)
Where did my ALT and CHOP triggers go? lol
Ah, Bee Did-El-Lee ...the good old days!
I was an ALT man myself
i actually have an old analog scope that also can trigger on alternating channels and the best thing is when only one chanel id active it always triggers on thr active chanel
Just curious, on an analog scope, I once made an 8ch digital input project that allowed an analog scope to show 8 channels on only one channel -- Thinking back on this, I could have used this technique to show compare pulsewidths of 8 pinputs.... I wounder if you could just use at the analog level, just put two diodes on the input to make an OR circuit to a dedicated trigger input, Ch1, Ch2, Trigger inputs on scope?
The GW Instek should have it. In the Trigger menu select Source and you should find Alternate
Another very useful scope tutorial, Dave. I will be giving this a try. This technique may prove useful on a project I'm currently working on. I need to monitor two serial data lines where one line outputs a signal in response to another. They are non-overlapping and at least a quarter second between them.
What would the use of a random trigger holdoff be? I guess just for hysteresis type reasons, since real signals are never as nice as proper training type signals? Only think I can really think of...
Thank you
I use an IWATSU SS-7810 which is a dual channel 100M analog scope and has both DLY and ALT trigger. Digital scopes in ALT or pattern or something like that uses software trigger which uses ADCed data for triggering, as a result many functions would be unavailable.
FWIW, I have a Siglent SDS 1052DL+ here that has an alternate trigger mode. So there is that.
How would you implement single shot with independent time bases? Wait until some or all have triggered once?
I guess it would be best if it´s configurable in the trigger menu.
I always warn my students that the ALT trigger setting (as it is called on our student lab's analog oscilloscopes) is a dangerous function, because it will - wrongly used - hide all phase relationship between the two channels. But yes, your case actually makes sense for these settings.
Yep, potential trap for young players.
Thanks Dave a most interesting video, I have a Tek TDS5054B which has the Logic/Pattern functions in the Avanced trig menue.
QUWHATT! (12:12) Scopeman talks about a feature on my DS1052E!!! I 'bout choked on my lunch. Thanks Scopeman :-)
Thanks for the info and especially the demonstrations across brands, BTW Now that you have the multimeters all set, when do you plan to design and start selling your own scope too? ;)
No..Power-supply...Power Supply (please Dave)
Okay, I can't disagree with you on that. :) Still, I think one of these companies should hire Dave to consult on the interface design for their scopes, laying it out as intuitively as he'd like it and eliminating all of the annoyances he finds with many of them. (It'd probably feature a big-ass knob that is clickable, pullable, pushable, top-hattable [?], has haptic feedback, plus an adjustment collar and a few pinkie buttons/slides for channel & mode... along with being fully touch-screen too, of course.)
On the pattern triggering two rising edges makes no sense for AND so maybe the UI just isn't smart enough to permit it when OR is selected...?
Good stuff. Adding this to my resume as we speak. A jack of all trades and a master of none... is my middle name.
yay, he's doing more scope tutorials! I was worried that this was turning into the solar roadway update channel for a minute there...
Altern-Ate! Long A! The triggers go back and forth, not to some other auxiliary source.
Do you own all of those scopes? I wish I can afford just one decent scope for home use.
13:42 - Kamagatsu? What is that word you keep using?
Reasons to keep my 453A...
Or use a very old dual beam oscilloscope.
Someone made a comment about selling your own scope,
I'm pretty sure you could design one.
Now that would be a great set of videos to watch.....
Definitely. He could test the viewership waters by designing a decent front end from scratch. That would be a good start and could be done in a practical way with lots of great analogue lessons. I haven't seen anyone upload practical content about analogue networks, auto ranging, attenuation, and driving an ADC. There are some uploads from various manufacturers, but I haven't seen anything from a neutral party/design perspective.
The high speed ADC and FPGA stuff would be interesting but less practical, at least for me. It's rare to find someone that can explain code in video format that has flow and can be followed. I doubt I would watch much about human interface design.
I have a feeling it would take one person quite a lot of time to design something like this. Filming, editing, and uploading content on the subject would easily extend the development time by an order of magnitude. I don't know how feasible this is.
I imagine Keysight might be interested in some kind of partnership, assuming their recent marketing campaign has proven fruitful. I haven't purchased a scope from them but they went from just another entry on my list of brands to explore to the top of my list based on Dave's exposure and the quantity of YT CC's I watch that use them now.
For me to consider a new scope it would either require some serious improvement in available features or a critical task I am unable to do with my scope before I'll go looking for a new one. I don't know how many engineers would buy something like a scope just because of it's branding/marketing. Plus what feature set and price point could he target. I'm a total entry level type customer, but I followed the best value option for my first scope. I can't imagine any amount of marketing could overcome this. The product would need to be at a near equivalent pricepoint value. Given the competitive number of products on offer, those most be some really tight margins within this segment right now. It would be interesting to see how such a thing could work. I'm skeptical, but I'd love to be proven wrong.
-Jake
Siglent SDS 1104X-E works also with OR condition and HIGH levels set. Thanks for the video and for the Arduino code. Arduino bitbanging happens to be glitchy though, so for a while I thought it's a problem with triggering. But no, Siglent in fact works well with this type of triggering.
Winner, winner bleached chicken dinner.
That's klooooooge, please!
Don't you generally have to be STOPPED for Single-Shot to work?
Nope
The scope stops *after* a single shot has triggered.
Pssst... I could pull this off with my Tektronix 475.
And a link for doing something similar on Rigol / Ultrasigma
rigol.desk.com/customer/en/portal/articles/2285624-programming-alternating-triggers
I used to make a lot of use of a dual timebase in "B trigger after A" mode. That lets you find an arbitrary event that comes after some other event.
Just for completeness, I should point out that it is easy peasy to analyze two otherwise asynchronous time uncorrelated signals using two oscilloscopes. I have on occasion used three elderly analog Tektronix scopes to see everything I wanted to see simultaneously.
Glad to see my SDS1104X-E is waving the green flag on this function.
My SDS1102CML has Alternate trigger option.
ESSENTIAL.... for niche applications ;-)
Dave - you've got too much time and too many scopes. :)
The other day a spoiler alert in a aircraft video.. now a trigger warning in a oscilator video.. :O
Cool
No! We want more oscilloscope videos!
OK TOTALLY TRIGGERED!!!
👍
I read the title of this video as "How to ALIEN Signals On A Digital Scope".
Same. Honestly only clicked to make this comment, hahaha.
First times infinity
I read "Alien signals". Can you imagine my disappointment :)?
♫ Here's a little lesson in trickery...
We need more teardowns tbh
I'll try and forego the useful and unique tutorial videos to bring you more teardowns...
@@EEVblog no!
@@EEVblog Or you could just accept a helpful suggestion of what your audience likes and be less sensitive and defensive. I've noticed more recently in live streams you've developed a bit of an angry streak, maybe its time for you to take a youtube break as being on here is clearly getting to you.
First
Just when I thought it was time to unsubscribe
Oh no, trigger warning. Better not watch. Bye.