Problem 2. We want to implement a digital filter with a desired frequency response H\left(e^{j \omega}\right)=\left\{\begin{array}{ll} 1, & \text { if } \frac{3 \pi}{4} \leq|\omega| \leq \pi \\ 0, &

\text { other wise } \end{array}\right. Determine the impulse response h[n] by using the definition of the IDTFT and plot h[n] for n =[-20, 20].