Updated: Sat 15, 2011 8:56 pm attached another file.
Viewing of small signals on a large DC offset voltage is a limitation on the DC coupled Nano (although unwanted ripple viewing is a common use for o’scopes). Another o’scope is the easiest solution, but the Nano is so small and portable. Another possible solution would be to offset the captured data by a DC voltage and amplify that offset value by a given gain factor to make that ripple signal more easily viewed on the Nano. None of this would impact the capture buffer, since the acquisitions could be stopped while in this mode, and only the screen display would change. The user would be able to choose from menu choices.
This is all predicated on the condition that the ripple signal always remains within the input voltage range of the Nano. The purpose of this post is to present data that will help to determine if this feature will provide expected advantages or not.
Attached are zip files that contains supporting files for initial analysis with a ripple signal riding on a constant voltage. The supporting files will be based up the 3 input stage gain ranges.
You don’t have to know a lot about Excel to view these results. Just unzip the file and load the *.XLS file into Excel and look at the test result waveforms on your computer screen.
To decode the attached file names below, the 1x=1xprobe, 02vd=.2V/Div, 5usd=5us/Div, 120hz=ripple freq, 200mv=ripple amplitude, PriPos=buffer priority, R3=range3.
Range-1 = 1x probe 10mv - 100mv/Siv
Range-2 = 1x probe 200mv - 1v/Div
Range-3 = 1x probe 2v - 10v/Div
Range-4 = 10x probe 10mv - 100mv/Siv
Range-5 = 10x probe 200mv - 1v/Div
Range-6 = 10x probe 2v - 10v/Div
1x2vd5usd120hz200nvPriPosR3.zip (87.9 KB)
1x1vd20msR2.zip (24.4 KB)
1x02vd20ms120hzPriPostR2.zip (34.7 KB)