I thought in the wrong direction, the half is needed only to normalize the channel…
I think I am always a rational and objective person. Even though others’ may not agree, I’m getting more confident about what I truly think.
I feel happy to understand myself, and I will be even happier when all these are proven to be true.
I believe that day, if exists, is close.
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.
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。