About modeling a narrow band fading system

The first project of the course required me to simulate a narrowband fading channel using Jake’s model. I thought that for many days but didn’t come with a solution.

Finally I understood that it is a problem about the understanding of the word “fading”. Fading is due to multi-path, and according to the previous course, multi-path communication will made the channel to be dispersive. However this is not the case for narrow band. In fact, narrow band means that the channel is approximated to be memoryless (neglectable inter-symbol interference), and different paths will “fade out” each other (by differing a phase) at that exact moment. The autocorrelation of the channel is to describe the “change of the channel itself in the time domain”, not “how the source signal are correlated with each other”. In other words, the received signal are correlated not because of inter-symbol interference, but because the channel is not time invariant. That’s why we made the assumption that the source is unmodulated.

Thus, the channel function h(t) means the change of the channel in the time domain, not the impulse response as we normally may think.

Sketch的gaussian blur

感觉sketch前年用的时候gaussian blur可能是带了zero padding的,今年貌似换成replicate padding了,感觉没办法弄回之前的头像了。。。不过也就是边缘的intensity上去了一点。总之希望这次coding没算错。不过如何interpret information的确是很有意思的。感谢信息论。

LGU这四年

这篇东西只是想放一些照片。LGU的各级组织向来喜欢拍照记录,本人在这几年也拍过各种年级相册、时光胶囊什么的。邻近毕业,翻翻相册,发现不少关于LGU的照片,也想和大家分享一下。部分图片经过Google Photo的自动增强。不允许转载。

2015年来LGU报到,难忘的是南方城市的蓝天
在信息学院的楼顶,第一个远离家乡的中秋节,华为MATE7刚刚新增了超级夜景功能,尝试了一下。远处是大运。
第一个在龙岗过的国庆节,沿着龙岗大道的地铁做到了终点站附近,看车来车往

在双龙附近的天桥上,当时的特区卫生让人触目惊心。深圳是一个很乱的地方,也是一个很有活力的地方。
搬来书院住差不多一年,一期工程也即将竣工
一个人溜到了还未竣工的上园看看。这里是教职工宿舍。
还没有彻底完工的上园书院顶楼。那段时间关于是上床下桌还是上下铺讨论纷纷。北欧实木的梗也是那时开始的
借了楼上实验室的Phantom 4 Pro去看了看灯火中的上园