AM-AM and AM-PM measurement of baseband to RF integrated circuits for ACPR calculations

A method to measure AM-AM and AM-PM characteristics of integrated circuits that operate with baseband inputs and RF outputs is presented. The technique requires control of the baseband input signal, three signal generators, and a vector voltage meter to make the measurement. ACPR calculated from the nonlinear transfer characteristic of two CDMA transmitter RFICs are compared with measured ACPR performance.