问题 问答题 简答题

高频已调波信号和本机振荡信号经过混频后,信号中包含哪些成分?如何取出需要的成分?

答案

参考答案:高频已调波信号和本机振荡信号经过混频后,信号中包含直流分量、基波分量、谐波、和频、差频分量,通过LC并联谐振回路这一带通滤波器取出差频分量,完成混频。

判断题

      上个世纪末,我国已达到小康水平,摆脱了贫穷落后,实现了初步繁荣富强,达到了中等发达国家水平。 

                                                                                                                                                               

                                                                                                                                                               

                                                                                                                                                                

                                                                                                                                                                

                                                                                                                                                                

                                                                                                                                                                

                                                                                                                                                                

问答题 简答题