題組內容

5. Let \( \{a_k\} \) be a sequence of data which is multiplied with a pulse shaping function \( h(t) \). The transmitted signal is given by \( x(t) = \sum_{k=-\infty}^{\infty} a_k h(t - kT_s) \). At the receiver, we sample this signal every \( T_s \) seconds to get the discrete signal \( x[n] = \sum_{k=-\infty}^{\infty} a_k h[n - k] \) for every integer \( n \).

ii) (7pt) Now, derive from part i) the condition on \( H(f) \), in frequency domain, which guarantees no inter-symbol interference.