Research On Linerization Of Short-wave Power Amplifiers

With the development of communication techniques, the linear modulation andbroadband communication have found wide applications. In the emitting equipment of amultichannel HF communication system, multiple single-sideband-modulation signalsare combine into a wideband signal with great undulate envelops because ofoverlapping in time-frequency domain. The wideband signal will result in seriousinter-modulation if it is amplified by a nonlinear RF power amplifier. Therefore,research on RF power amplifier linearization is of great significance, which canremarkably reduce inter-channel interference resulted from the inter-modulation.After introducing the basic knowledge of HF communication and analyzing itsmain characteristics in depth, this thesis summarizes the progress in the research onRFPAL at home and abroad. Through comparison analyzing various methods of RFPAL,the thesis indicates that the pre-distortion technology is fine and mature and has foundwide applications.Considering the requirement of further development of HF communications, e.g.3G-ALE(3G Automatic Link Establishment), RF digitization, service digitization andlatticizing applications, we chose the pre-distortion technology as an RFPAL method,and have it practically implemented for linearizing an HF power amplifier. Furthermore,it has been verified by using some a125W power amplifier, and the test results showthat it can reach the target of remarkably improving the linearity of an HF poweramplifier.