I think that is exactly what the scope should do. If there are multiple triggers within one frame-time of the screen it should show all the events within this time, no? I thought that is what intensity grading is based on. So if you have two qualified trigger events within 16ms (assuming 60Hz LCD refresh rate; I know this is simplified ) then I would like to see both, no? Or should one just be thrown away? Do i miss something?The problem is that with 2 signals on screen you have no clue what is being decoded so yes, that is a problem.
I think that is exactly what the scope should do. If there are multiple triggers within one frame-time of the screen it should show all the events within this time, no? I thought that is what intensity grading is based on. So if you have two qualified trigger events within 16ms (assuming 60Hz LCD refresh rate; I know this is simplified ) then I would like to see both, no? Or should one just be thrown away? Do i miss something?
Michael
Seems like the answer then is triggering on what you want to see rather than randomly triggering on edges to see data or performing single shot captures rather than forcing trigger while it's sampling normally.
There cannot be several trigger events on same screen scan.
I think that is exactly what the scope should do. If there are multiple triggers within one frame-time of the screen it should show all the events within this time, no? I thought that is what intensity grading is based on. So if you have two qualified trigger events within 16ms (assuming 60Hz LCD refresh rate; I know this is simplified ) then I would like to see both, no? Or should one just be thrown away? Do i miss something?
Michael
Seems like the answer then is triggering on what you want to see rather than randomly triggering on edges to see data or performing single shot captures rather than forcing trigger while it's sampling normally.
I understand now what are you saying, and no, it doesn't work that way. You have a trigger, then scope disables triggering, it scans full screen to the end, rearms trigger, and waits for new trigger condition.
There cannot be several trigger events on same screen scan. Signal cannot be two different signals at the same time. You can have only one signal value at any given point in time.
I think that is exactly what the scope should do. If there are multiple triggers within one frame-time of the screen it should show all the events within this time, no? I thought that is what intensity grading is based on. So if you have two qualified trigger events within 16ms (assuming 60Hz LCD refresh rate; I know this is simplified ) then I would like to see both, no? Or should one just be thrown away? Do i miss something?
Michael
That isn't true at all. A DSO which can do several thousands of waveforms/s has to stack multiple waveforms into one screen refresh cycle (usually 60Hz). This has been explained on this forum many many times already.
Normally this isn't a problem (and depending on the persistence setting wanted behaviour) but when using protocol decoding it is making it hard or even impossible to see which signal is being used for decoding.
I should clarify: with one screen time I don’t mean the time it takes the “beam” to go from left to right. I meant the refresh-rate of the display. So of course if your timebase is 10us and you have 10 horizontal divisions then the trigger will be disabled for at least 100us (if we assume no pre-trigger). But after those 100us it can trigger again. So if we refresh the display let’s say 10 times a second, we have 100ms of time to capture, in the best case, 1000 waveforms. And all of those can be shown (intensity graded) on the screen. If the waveform has two different pulsewidth (and you trigger on the rising edge you will see two falling edges on the screen. If you don’t use a more complex trigger, you can’t get around that (except maybe a long trigger hold-off).
P.S.: I know that the numbers may not be fully realistic, I took those just to make a point.
Michael
I'm probably about to pull the trigger on either
a RTB2K-COM4, and have a good 300MHz scope with everything that I need (~3.8k EUR w/o VAT)
a RTB2K-74M and see if I can hack it (~1.8k EUR w/o VAT)
a MSOX2024A with a bunch of options, used, from keysight's ebay, for 2.2k$
Any comments or alternatives I haven't considered?
GW Instek MSO2204E . Price wise between all of them and it does give you deep memory and protocol decoding. I wouldn't consider the MSOX2024A because the memory is too small.
Thanks for the pointers. Keysight hasn't been too attractive especially because of low memory and no warranty.
Education (student) discount from Datatec is ~30% for the -COM4, and I get the VAT back.
I'll look into the MSO2204E. Seems like a good option. -COM4 is still super attractive but also quite a bit steeper in price.
Just today while checking the firmware page, the new firmware 2.101 is gone and what's there is the one released last Nov. 2017. What happened? Did I miss something?