It seems to me that basic oscilloscopes show waveforms that repeat or are periodic. Is there a type of scope that can be used to just display the waveform between two specified times, or that can scroll across time?
Moved your thread to the Oscilloscopes forum for traction.
There are two primary types of Scopes: Sampling, and Real-Time. Your description applies mostly to Sampling scopes. Real-Time scopes can capture single events, and non-repeating waveforms. For slower changing waveforms, many real-time scopes include a display mode, called roll mode, that scrolls that data across the screen. If you have a specific trigger condition that occurs regularly, but the waveform around that condition changes, there is a mode called segmented that will capture many occurrences of a short period of time
What are you trying to capture?
No real problem. Just a general question. I had looked at an intro for oscilloscopes the other day and was surprised that in this modern age that we were still dependent on setting some trigger level to get the scope to display correctly. I would have thought that in this computer information era, the art would have evolved to something more sophisticated. I have in mind grabbing a file of data and displaying it interactively. Perhaps the new scopes can do this, and it was just that the introductory treatment that I had looked at did not get to this level.
Just the 'musings of a theoretician' really. No real need on my part. But thanks for your answer.
In general, the scope doesn't know what "display correctly" means.
You don't really need a trigger, but without it, the scope doesn't know what portion of the waveform you are interested in. You might be interested in problems like narrow pulses, slow rise times, etc. all of which are 'triggerable' events
Most scopes support an autoscale function which tries to adjust the vertical and horizontal settings, along with the trigger, to get a good picture. It works pretty well for regularly occurring digital signals, but gets bolluxed up by things like pulsed RF.
Most scopes can 'grab a file of data and display it interactively'. I use that capability daily. For that you don't need a trigger, but the file will generally have time stamps, relative to some '0' point, which is quite often the trigger. For most processing, such as jitter measurements, the trigger is ignored, since you are interested in location of various events relative to each other, without regard to the trigger.
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