I've build a small op-amp circuit that is being driven by the stock standard "tone follower" sketch in the examples. No problem there. As expected it outputs a square wave. (Arduino Uno)
I've noticed a very high frequency on the positive pulses with my oscilloscope. I got about 33Mhz 2mV perfect sine superimposed on the trace. Even straight from the board I get this noise. My scope's grounded properly and I use GND on the Arduino as my scope ground as well. I'm sure this is the clock frequency of the UNO.
What is a quick and safe way of blocking the stray signal from my output? Even the blinky LED have this signal superimposed on the pulses. Its no serious matter right now as I'm mostly fooling around, but it did give me some problems driving my op amp. (For some reason, that signal goes in one side and out the other, although I think that is more to do with my breadboard layout than anything else.)
Thank you