Communication Signal (CS)
Question 5: Image Processing
August 2017 Problem 2
Solution
a)
$ sinc^2(\dfrac{t}{a}) \Rightarrow |a|\Lambda(af) $ (CTFT)
b)
$ y(n)=sinc^2(\dfrac{nT}{a}) \Rightarrow X_s(f)=\dfrac{1}{T}\sum_{k=-\infty}^{\infty} X(f-kF)=\dfrac{|a|}{T}\sum_{k=-\infty}^{\infty}\Lambda(a(f-\dfrac{k}{T})) $
c)
minimum sampling frequency $ \dfrac{1}{T}\ge\dfrac{2}{a} $ $ f\ge\dfrac{2}{a} $ $ T\le\dfrac{a}{2} $
d)
$ T=\dfrac{a}{2} $
e)
$ T=a $
