I am having problems figuring out the best way to isolate sense lines, filter noise, and avoid ground loops. Here is the situation:
- Sense multiple points on a DUT board (extremely noisy environment).
- Drive the sense signals along ~50ft of 50ohm coax.
- Measure the signals with Scope(s). Using standard BNC input, differential probes are not an option.
I am using a single ended Hi-Speed buffer LH0063 (very high slew-rate and very high input impedance), click here for datasheet
I have to use this part. I cannot swap it for a different signal driver. The driver(s) can go unstable. If there are ground loops or multiple drivers not correctly decoupled or driver lines to close to sense lines, the output will oscillate.
Here are 3 scenarios I came up with. I don't know which is best or if I should do a combination, or what changes I should make. Any feedback would be helpful.
ALL TRANSMISSION LINES ARE 50ohm BNC cables
SENSE SIGNALS ARE IN ~10MHz frequency range