Yes i know, but when i record the signal with 20ms/div and the other one with 50ms/div i can not compare it
I can't give you a tutorial in a forum post on how to use Pico Views and Reference Waveforms. Basically reference waveforms, scope views, zoom window, and scaling are how you accomplish what you want to accomplish. I learned how to do this through Autonerdz membership resources. I do not know of a resource that explains the process which is available to people that are not Autonerdz members.
I am reading this discussion and honestly, I also believe the time base should be possible to change on the saved waveform file. It could be by either loose or hide some data when "zooming in" or create no data (half empty waveform screen) on right side of the screen when "zooming out like" (lets say max one step). It would make it all easier for sharing the waweforms with other users, especially the lesser experienced users.
I personally do not have any issue with no timebase change but if something can be easier then why not.
Cheers,
Roman