论文部分内容阅读
一引言在广播,电视,通讯等过程中,为了远距离传送低频信号或视频图象信号,必须把这种频率较低的信号调制到较高频率的载波信号上,经过放大等,再由天线发射出去。调制的方式有调幅,调频,调相等三种。目前用得较广泛的是调幅和调频。调幅制虽用得很广泛,其技术也较成熟,但是调幅制在高等院校有关专业的电子技术课程的讲授中,往往只有数学推导和理论性的分析,而实验观察与研究却很少。在大部分高等师范院校物理系的电子技术实
I. INTRODUCTION In the process of broadcasting, television and communication, in order to transmit low-frequency signals or video image signals over long distances, it is necessary to modulate such lower-frequency signals to higher-frequency carrier signals, amplify them, Launch it. Modulation methods AM, FM, FM and other three. Currently more widely used is the AM and FM. Although the amplitude modulation system is widely used and its technology is relatively mature, the AM system is often given only mathematical derivation and theoretical analysis in the teaching of relevant professional electronic technology courses at institutions of higher learning. However, there are few experimental observations and studies. In most of the higher normal school physics department of electronic technology reality