I currently have 4 signals (+/- excitation and two returns) going between point A (where the two returns are amplified) and point B (a loadcell/Wheatstone bridge). I have a small circuit at Point A (mostly containing the instrumentation amp), but my plan is to replace it with a much larger circuit board. Currently, the four signals go from A to B in the form of a shielded cable, with the shielding being drained/grounded on one end (the Point A end). But in my envisioned design, the circuit board would cover most of that distance (about 6 inches) itself, so that the four signals would run along traces in the new PCB. Note that I am shielding these signals because I have a nasty stepper motor sitting nearby. So, my question is...how do I duplicate/simulate the shielded cable when I switch over to a pure board design? My gut says that I should have a multilayer board with these particular traces on one layer, and with ground planes both above it and below it. Of course, these ground "planes" would not have to cover the whole area of the board, I am telling myself. It seems they should follow the four traces, but extend out on either side by a half-inch or so? So they would basically be two inch-wide sheets of copper, following the exact path of the traces sandwiched between them. However, I haven't read much about this sandwiching technique when it comes to PCB design. Do I have this all wrong? Do I only need one ground plane? I could really use some advice, as I may need to build 15 or 20 of these machines quite soon.