A powerful, but an underused feature of digital oscilloscopes is the trigger circuit. Learn from James how to use an oscilloscope’s trigger to find glitches, measure pulse widths, see transients, and stabilize a scope’s screen. This video explains the difference between Auto and Normal sweep modes, shows how to use a Pulse Width trigger, and explains how to use Hold-Off.
Every digital oscilloscope I have ever used has a menu or dialog for “acquisition modes.” And depending on the current settings, changing that acquisition mode does not seem to have an effect on the signal. Or sometimes, changing to something like Average mode can completely destroy your measurements.
It turns out, that the analog-to-digital converters in digital oscilloscopes can do more than just “sample” the data. Well, the ADCs just samples. The controller behind the ADC offers modes like Peak Detect and Average and High-Resolution.
In general, the key to these modes is looking at a signal that is relatively slow compared to your sample rate. For example, on my R&S RTM3004, it samples up to 5 gigasamples per second. However, if you are only looking at a 10 MHz clock with a rise time in the 10s of nanoseconds, you don’t need to sample that fast.
Or, more correctly, you do not need to STORE data that fast. An acquisition mode, like Peak Detect, reduces (or decimates) the information stored. For example, it might look at 4 samples and ONLY store the max and min values of those four. That way, you get half the effective sample rate, but your peak-to-peak voltage measurement will still be correct!
This Workbench Wednesdays video looks at various acquisition modes and addresses when to use Peak Detect, Averaging, and High-Resolution acquisition modes.
One of the best ways to learn how to use a new piece of test equipment is to use it. Sounds easy, right? The problem is, sometimes when you are in the middle of troubleshooting your circuit, figuring out what the knobs on your scope do is an immense frustration. Use these 6 oscilloscope measurements, and just an Arduino Uno, to learn how to use a new or unfamiliar digital scope.
This tutorial is not a step-by-step guide on how to make each of these measurements on a particular scope. Instead, it is a general explanation on how to setup the Arduino and a screenshot to help identify if you set up your scope correctly. I reference the R&S RTM3004. However, practically any two (or more) digital channel oscilloscope should work.
Between each measurement, I highly recommend using your scope’s default setup (or autoscale) before proceeding to the next one!
