Diff Probe Noise

Hi there,

I’m using the diff probe and the signal seemed noisy. So I unplugged everything leaving only the chipwhisperer, the probe power supply, and the prob connected, and the probe is reading rapidly changing values between -0.2 to +0.2.

Is this expected behaviour? I would have expected a pretty flat line with given no inputs connected.

If I unplug the probe power supply I get a barely visible, and almost unchanging line.

Image of the probe with no inputs connected, and the power trace graph: https://m.imgur.com/a/duP034a


I believe by default the inputs for the differential probe are high impedance, meaning if you leave them disconnected they’ll pick up a bunch of noise. Try connecting both inputs to ground and see if you still pick up noise.