A load pull measurement setup allows independent impedance tuning at RF frequencies at the output of the DUT as well as independent tuning at RF and baseband frequencies of the modulated signal at the input of the DUT. This allows optimizing baseband frequency impedances for nonlinear amplifier performance when processing modulated signal, such as IMD, ACPR etc. Baseband tuning is done using a low frequency programmable impedance tuner, which is connected through the input bias tee, which acts as a frequency separator (diplexer). The input bias tee may be an LC based network or a 3dB matched coupler based network.
A Load and Source Pull Test System for RF and Baseband Frequencies / 9,310,410
Tuesday, April 12, 2016