Here is what I would like to do. I’m observing a signal that I would like to record from, say, 1second before the trigger, an until, say, 5 seconds after the end of the signal. So the signal length would be variable, from T1-1 to T2+5 (T1 and T2 being 2 triggers).
Is it possible to set 2 triggers?
So basically I would like to:
Press play, which would cause the analyser to wait for the trigger
At trigger time, start the record
At 2nd trigger (or after some timeout): stop after 5 more secods (or whatever time)
There isn’t a way to do it exactly how you want, but you can set ‘Capture Duration Before and After Trigger’ as per:
… and then trim to exactly what you want:
So, set the ‘Capture duration after trigger’ to at least “timeout + 5s”, and then trim all data (after this point or marker) from T2+5s in you capture.
As long as your PC has enough RAM, it is easier to ‘capture everything’ and post-process, than set complex triggers. That is a key benefit of how this new hardware works – you just turn on/off the HD video camera, rather than set the perfect photo snapshot (one-shot) trigger. You can definitely use triggering modes, even based on decoded protocol data, but I often just use looping mode and manually start/stop the capture before trimming/zooming to the part I’m interested in saving/viewing further.
There is a loft of power in doing this on the PC side, but you have some drawbacks:
higher sample rate analog (especially on multiple channels) requires a lot more memory and USB bandwidth
(more sensitive to PC performance specs and other USB traffic)
analog sample rates are not as good as real oscilloscopes (max of 5 MHz bandwidth, 50 MS/s sample rate on ‘pro’ series)
lower dynamic range (only +/- 10 V for ‘pro’), and only 1X probing built-in (at 2 Mohm impedance)
limited digital logic voltage levels
(i.e., the threshold for turning analog voltages into digital ‘1’ or ‘0’)
However, it is way better than any traditional scope/MSO for doing logic analysis of digital data. The data storage of digital is per edge vs. per sample, so you can record at the maximum digital sample rate w/o worrying about wasted storage: you’ll just get higher resolution timestamps to be more precise on digital edges. Likewise, lots of analyzers/decoders with both low-level and high-level SDKs to turn hardware voltages & digital signals into more meaningful data.
Bottom line: let go of the idea that it is an oscilloscope, and embrace & learn how powerful the new tool is for debugging hardware digital (+ lower bandwidth analog) signals. It would take a different product design to overcome the limitations above and behave more like an MSO w/ oscilloscope-like analog features vs. a USB logic analyzer w/ analog channels
