$(50$ points$)$ Consider a High$-$Speed Serial Links $4-$PAM wireline communication sys$-$

tem design. Signal bandwidth is assumed to be $50$GHz$.$ Assuming that an ideal

shaping filter and Nyquist sampling rate, let $h[n]$ be a discrete ISI channel coeffi$-$

cients with length of $3,$ which are assumed to be $\{h[0],h[1],h[2]\}=\{0\mathrm{.}9,0\mathrm{.}42,0\mathrm{.}1\}.$

$($d$)(10$ points$)$ Plot the magnitude and phase responses of $H(e^j)$ using MATLAB

program.

$H(e^j)={\displaystyle \underset{n=-}{\overset{}{}}}h[n]e^{-jn}=0\mathrm{.}9+0\mathrm{.}42e^{-j}+0\mathrm{.}1e^{-j2}$