Theory and experiments of a low sampling frequency broadband digital predistortion with cyclostationarity.

Summary: To reduce the sampling rate from analog to digital converter for the feedback loop of digital predistortion (DPD) in a microwave power amplifier (MPA), a model was proposed and used to obtain the formulae for the cyclostationarity of the digital modulation signal, which shows that the nonlinear parameter of the MPA model is only determined by the correlation matrix of the signal and can be estimated with the under‐sampled output signal. The output signal of the MPA, similar to a high sampling rate, can be recovered by combining the nonlinear parameter with the input signal. Then the DPD of the MPA is implemented through indirect learning architecture to realize its linearization. A Ka‐band traveling wave tube amplifier is used to the circuit for performing a low sampling rate DPD process to validate the rationality of the proposed model and formulae. [ABSTRACT FROM AUTHOR]