Stackup approval to representative coupon and TDR recordsDesign estimate → agreed build → representative test1. Release the stackupNet class / layer / referenceTarget and agreed toleranceFinished W, T, H/B and Dk basis→2. Define the couponRepresentative layer and geometry→3. Agree TDR evaluationA coupon checks a representative fabricated transmission line.It does not certify every connector, via transition or complete channel.³Ô¹Ïtv · Engineering illustration · Not a measurement or a released stackup