Time-Frequency Characterization of Long-Term Memory in Nonlinear Power Amplifiers

This paper presents a new time-frequency characterization method for extracting the linear and third-order nonlinear parameters of a PA including long term memory. A dynamic frequency two-tone test signal is developed where the frequency separation between tones increases over time to enable third-order measurements over frequency from a single measurement. A measurement technique is presented using a single Vector Signal Analyzer (VSA) measurement to coherently capture both the test signal and the DUT output sequentially by switching between the two paths during the measurement.