It is possible to approximately relate the 1 dB compression point to the third-order intercept point. For a single-tone input, use (10.40) to find the amplitudes of the fundamental and third harmonic terms, and assume that a3 is of opposite sign to a1. Let V0 be the voltage where the third-order term reduces the first-order power by 1 dB, and solve for |a3/a1|. For a two-tone input, use (10.43) to find the amplitude of the third-order intermodulation product, then use (10.44) to relate OP1dB to OIP3.