| Along with quick development of the correspondence system, the amount of consumer increased quickly. In order to increase the capacity of channel, the frequency of carrier wave moved to higher endlessly. For the sake of the utilization of the exaltation frequency, various kinds of modulation technology extensive adoption among communication system. All these have put forward higher demand to linear degree of the communication system.In this paper we study the nonlinear characteristic of microwave power amplifier system, introduce the basic principle of feedback, feedforward and pre-distortion technical to linearize, analyze the basic feedforward power amplifier system on the time and frequency field. The Cancellation Performance of cancellation loops, which constitute the feed-forward amplifier system, and the overall amplifier efficiency is investigated mathematically, and simulation of the basic feedforward power amplifier system is run on ADS.This paper presents a hybrid linearization technique that integrates RF predistorting and adaptive technique into the structure of the basic analog feedforward linearizer to overcome many drawbacks of the basic feedforward power amplifier system. This hybrid linearization technique insert a RF predistorting unit in front of the main amplifier and select rational adaptive technique according to its working principle, so the linearity and power efficiency can be enhanced and increase the performance and practicability of whole amplifier system. Simulation is run on ADS to demonstrate the capabilities of the hybrid linearizer. |
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