The Adaptive Digital Predistortion Technology And Realization Using FPGA

HPA(High Power Aplifier) is an indispensable key component in the communication systems, moreover the main power devices. The quality of its linear has direct relationship with the size of the out-of-band emission and the adjacent channel interference. The efficiency of the HPA also determines the entire system power consumption. In the case of power limited, it decides the life time of the whole communication systems.This papers analyse the characteristics of the power amplifier and its non-memory and memory model and have done a detailed briefing of the adaptive algorithm and the predistortion algorithm based on lookup tables in the adaptive digital predistortion technology. This papers detail the exchange between Cartesian coordinates and polar coordinates, the elimination of frequency offset, the question of delay compensation which appearing in the process of the hardware implementation. Improve the "direct-fed" predistortion programme without memory structure for anti-noise performance, then analyse its performance and make mathematical simulation. After implementation using FPGA, the experimental results shows that the noise reduction programme is obviously effective. But under the experimental conditions HPA systems having a certain degree memory, the effect for interference suppression is not complete.