通信相关的文章收集

IQ调制：http://blog.chinaaet.com/molf/p/29748

通信介绍：https://zhuanlan.zhihu.com/p/23612006

https://www.cnblogs.com/shaoyou/p/4822222.html

https://en.wikipedia.org/wiki/File:Fourier_series_and_transform.gif

https://en.wikipedia.org/wiki/File:Fourier_series_square_wave_circles_animation.gif
https://en.wikipedia.org/wiki/File:Fourier_series_sawtooth_wave_circles_animation.gif