Analog predistortion RF high power amplifier design
|School||Huazhong University of Science and Technology|
|Course||Microelectronics and Solid State Electronics|
|Keywords||PA Linear Technology Analog predistortion|
Power amplifier can power signal amplification in order to launch a wireless communication system is one of the core components , the linearity and efficiency has always been the focus of attention . Nonlinear distortion be a wireless communication system to produce many adverse effects, such as the transmission modulation signal constellation shifted , eye closure causes difficulties demodulation , bit error rate increases ; within the bandwidth of the modulated signal power to the adjacent channel leakage , thereby interfering with adjacent channel communications. Although the application of power back-off method can improve the linearity, but it will be a corresponding reduction in efficiency. Therefore, a more advanced linearization techniques , while ensuring the efficiency, reduce the nonlinear distortion. This paper first introduces the basic amplifier design theory and common nonlinear effects , focusing on the amplifier memory effect and reduces memory effect method , and then introduces several common principles linearization technique and the corresponding advantages and disadvantages , indicating analog predistortion technology superiority. Based on the design specifications , the paper analog predistortion power amplifier design and simulation. Gives the driver stage and the main steps of the detailed design of the power amplifier , and the analog predistorter each module , a special study , detailing the non-linear generators , phase shifters , attenuators, delay the principles and conduct the simulation. Finally, the analog predistortion system based on the design , the production of the analog pre- distortion power amplifier 120W and debug the system and measurement . Ultimately output 120W , the two-tone signal frequency spacing 100KHz to 2.5MHz range, the system third-order intermodulation are less than -40dBc; dual tone frequency interval 2.5MHz in place, output 120W , the third-order intermodulation (IMD3) improved 10dB power added efficiency of greater than 30%. Power amplifier linearity and efficiency have been some improvements , to meet the design specifications .