射频功率放大器的线性化

【作者】 石海霞；

【导师】 敬守钊；

【作者基本信息】 电子科技大学 ， 电路与系统， 2005， 硕士

【副题名】预失真线性化器的研究

【摘要】 随着无线通信技术的飞速发展,线性调制技术正得到越来越广泛的应用。但包络变化的调制信号经过线性不良的功放后会产生互调分量,因此必须采用线性化技术来减少由此产生的邻道干扰。基于预失真技术的线性化系统具有技术简单易行,成本低廉的特点,因而获得了较为广泛的应用。本论文首先介绍了功率放大器的基本原理,分析了功率放大器的非线性特性,特别是AM/AM 和AM/PM 转换特性;接着介绍了常用的功率放大器的线性化技术,例如预失真和前馈技术,重点介绍了预失真技术。论文最后具体叙述了本课题采用的方案,说明了其线性化的原理及实现过程,并给出了放大器使用和不使用线性化器的结果,这些结果表明失真得到了改善。更多还原

【Abstract】 With the rapid development of wireless communication the linear modulation methods are widely used. Since the envelope of modulated signal fluctuates, these methods generate unwanted intermodulation distortion (IMD) products in a nonlinear Radio Frequency (RF) Power Amplifer (PA) . So it is necessary to use linearization technique to reduce the adjacent channel interference (ACI). Predistortion is a widely used linearization technique because of its unique advantage of easily realization and reasonable cost,and the research of predistoring linearizer is becoming the hot research field. The principle of power amplifier is introduced at first in this paper, The nonlinear influence, such as AM/AM and AM/PM conversion, has also been analyzed in this paper. Some common linearization techniques, such as feedback, feed-forward and pre-distortion, have been introduced and predistortion has been especially described. At last, the scheme of subject and the principle of this linearizer is represented and analyzed in detail, and the results for the amplifier with and without linearizer are given. The results show that distortion reduction could be achieved.更多还原