Overview The 3GPP Long Term Evolution (LTE) initiative is intended to provide a framework for the evolu- tion of 3G toward a high-data-rate, low-latency and packet-optimized radio-access technology. Its aim is to achieve a peak downlink cell data rate of greater than 100 Mbps and an increase in capacity of three to fi ve times compared with HSDPA (in the same bandwidth), with latency as low as 20 ms. While LTE has the potential to enhance 3G networks and enable signifi cant new service opportunities in mobile TV and video, achieving success in consumer-enabled devices will not be easy. Among other things, it will require the engineer to pay close attention to the power amplifi er (PA); a component which plays a key role in the LTE transmitter’s RF front-end. The PA contributes signifi cantly to handset power consumption and as an active device, exhibits nonlinear behavior which can be problematic. LTE’s evolved Node B (eNB) power amplifi er faces a similar problem and is compounded by the fact that it can be multi-carrier or even mixed-carrier. Optimal LTE system performance demands that the PA be both highly effi cient and linear. Accurately testing the PA during design and optimization provides one means of achieving this goal.