# Understanding Discrete Filters

#### Minchuu

Joined May 13, 2021
17
Hello!

I have already done the requirement. I just need a little help understanding why it worked and not just being robotic about just following the instructions. So I have a multipath channel with [num,den]=[exp(-0.01*(0:50)),exp(-0.005*(0:100))] and it was corrected with a filter with [num,den]=[ exp(-0.005*(0:100)) , exp(-0.01*(0:50))].

I understand that the filter cancelled out the effects of the channel. I was hoping to understand how and why. I tried getting the z-transform the channel and use the poles and zeroes of the filters to solve it, but it doesn't cancel out, per se? It's not equal to 0, at any rate. Or maybe it doesn't work that way?

Anyway, I just wanted to back the exercise with mathematics for my own better understanding, but it just managed to confuse me more.