| In the field of mobile communication, network optimization is a constant theme in the maintenance work of operators. With the development of the domestic GSM communication system ranging from network coverage to superior network, optimizing the original network is becoming a keystone. Base station power amplifier is a kind of technology which has got speedy prevalence and successfully applied at home .It has great superiority in elevating base station capability and improving network service quality. Many operators in Europe take it as a key means in GSM network Optimization and operators in many Asian countries and areas are adopting it too. Along with the network optimization going deep insistently, base station power amplifier has prospects. The major task of this dissertation is to develop a 900MHz 20W GSM base station power amplifier module. Concerning the power amplifier. in the whole course of design, simulation, debugging, testing etc. work of 4 aspects is chiefly carried out as follows :1. Theoretically deep analysis is made which is about characteristics of suppression on nonlinear frequency about quadrature balanced amplifier. Moreover, with the help of modeling simulation, it is testified that the kind of amplifier can't improve the IM3 remarkably.2. Separately adopt High Gain Project and High Power Digital Attenuator Project to solve the problem of realizing higher precision numerical control 0~7dB adjustment function under the high input power of 5W.3. A kind of amelioration type temperature compensation circuit is adopted. As the consequent, compensation limitation brought by discreteness of threshold voltage of power device is solved effectively in the common temperature compensation circuit. So, compensatory consistency is better, is more fit for mass production.4. Introduce the designing idea of Load Pull to the debugging course of Power Amplifier and bring out high linearity power amplifier of third-order intermodulation lower than -40dBc. |
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