Work out channel insertion loss instantly with clear inputs, formula shown and shareable results.
Channel loss is trace loss per inch at the Nyquist frequency times the length, plus connector, via and package contributions. Standards define a loss budget — around 28 dB for PCIe 5.0 at 16 GHz — and exceeding it means a retimer rather than more equalisation.
Insertion loss
total = length (inches) x loss per inch at Nyquist + connector and via losses
Because that is where the fundamental of an alternating bit pattern sits, and it is the worst case the equaliser must recover.
Higher dielectric loss tangent, rougher copper (skin effect on surface roughness) and narrower traces. Low-loss laminates and smooth copper are why high-speed boards cost more.