A Digital Predistortion Method for Fast Frequency-Hopping Systems

Digital predistortion (DPD) has been widely used to linearize the power amplifiers (PAs) by capturing the PA nonlinear distortion and pre-distorting the PA input. However, both the capturing and the signal processing procedures are time consuming and not applicable to fast frequency-hopping systems. This paper explores the feasibility of constructing a wideband signal to extract DPD coefficients for frequency-hopping systems. The frequency range of the wideband signal is designed to cover all hopping frequencies, as such the nonlinear characteristics of the PA at all hopping frequencies are included during the estimation of the DPD coefficients. Thus, only one set of coefficients is needed to linearize the PA over a wide frequency range. Experiment is performed on a self-designed testbed, which demonstrates that the proposed method can be used to effectively linearize the narrowband signals over different carrier frequencies.