전자공학회논문지A (Journal of the Korean Institute of Telematics and Electronics A)
- 제31A권5호
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- Pages.68-75
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- 1994
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- 1016-135X(pISSN)
Feedforward 방식을 이용한 Predistortor에 관한 연구
A Study on Predistortor using the Feedforward type
초록
A new Predistortor that is designed using Feedforward type is proposed to overcome the nonlinearity of HPA (High Power Amplifier). HPA has the nonlinearity of the gain compression and phase distorton, so digital communication system of multi-carrier TDMA needs the linear RF transmitter. Using IMD (Intermodulation Distortion) of drive amplifier, as Feedforward type, the inverse IMD is coupled to the main loop with variable attenuators, phase shifters, and sub-amplifiers well designed. At the input of main amplifier, the over-coupled IMD surpresses the main amplifier 's IMD. Adjusting the level and phase of IMD at the sub loop, C/I of HPA is better than before correction.
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