摘
要
放大高频小信号（中心频率在几百KHZ到几百MHZ，频谱宽度在几KHZ到几十MHZ的范围内）的放大器，称为高频小信号放大器。这类放大器，按照所用器件可分为晶体管，场效应管和集成电路放大器；按照通过频谱的宽窄可分为窄带和宽带放大器；按照电路形式可分为单级和级联放大器；按照所用负载性质可分为谐振放大器和非谐振放大器。所谓谐振放大器，就是采用谐振回路作负载的放大器。根据谐振回路的特性，谐振放大器对于靠近谐振频率的信号，有较大的增益；对于远离谐振频率的信号，增益很小。所以，谐振放大器不仅有放大作用，而且也起着滤波或选频的作用。高频小信号调谐放大器广泛应用于通信系统和其它无线电系统中，特别是在发射机的接收端，从天线上感应的信号是非常微弱的，这就需要用放大器将其放大。本文以理论分析为依据，以实际制作为基础，运用LC电路的谐振作为选频和滤波，利用三极管的放大作用来实现小信号放大的作用。关键字：三极管；LC电路；放大器；高频小信号
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1绪论111高频小信号调谐放大器r