Hi Stephen, >it looks like it has something to >do with the signal itself, almost like the "pre-ringing" of a perfect >low-pass filter
Given that your cutoff frequency is 60MHz, the leading edge of the signals you are seeing probably bear little relationship to the actual state of the signal. I say this as the sparkgap type circuit you are using can generate sub nanosecond risetimes. And the measured risetimes just happen to correspond to your scopes bandwidth limit. >Without more experiments it's impossible to say for sure what's going on >here but my first guess is self-inductance in the loop. That's a good/reasonable guess. Are you interested in doing more experiments to prove it out? As the current experiment seems to be showing the opposite of the claim in the message header. K.
