Edit: As mentioned in later posts, I had assumed that most DSOs could be set to Edge trigger on
either (i.e. every) Rising and Falling edge (as Rigol, Agilent, R&S, Instek DSOs do). This appears to be incorrect - and that many (all?) of the lower-cost ones will only trigger on
alternate Rising and Falling edges.
![](https://www.eevblog.com/forum/testgear/a-simple-technique-to-measure-waveform-update-rates-on-dsos-with-no-trigger-out/?action=dlattach;attach=48373)
If you're not sure if your DSO supports
every Edge, you can test very quickly by setting it to 5ms/div, then sending it a
sine wave (DS1000 series won't work with square waves) between 1 - 12Hz (step 1Hz). If none of those frequencies produces a stable, non-moving waveform on a single edge, then your DSO is skipping potential triggers - and this technique won't work.
![](https://www.eevblog.com/forum/testgear/a-simple-technique-to-measure-waveform-update-rates-on-dsos-with-no-trigger-out/?action=dlattach;attach=48421)