An apparatus, method and work product is disclosed. The method comprises measuring plural transmit signals and corresponding receive signals and determining, using a model describing a relation between each of the plural transmit signals and a respective passive intermodulation signal, a standardized passive intermodulation signal as one or more nth order intermodulation products for a standardized transmit signal consisting of two tones each of a power of substantially 20 Watts. The method may also comprise identifying in the model one or more nth order cross-intermodulation products resulting from three or more transmit signals having different respective carrier frequencies. Responsive to the identification, the method may comprise adapting the standardized two-tone passive intermodulation signal by determining an offset for producing an adapted two-tone standardized passive intermodulation signal, n is an odd integer greater than two.