Consider a pulse s(t) = sinc(at)sinc (bt). where a z b. (a) Sketch the frequency-domain response S(f) of the pulse. (b) Suppose that the pulse is to be used over

an ideal real-base band channel with one-sided bandwidth 400 Hz. Choose a and b so that the pulse is Nyquist for 4PAM signaling at 1200 bits/s and exactly fills the channel bandwidth. (c) Now, suppose that the pulse is to be used over a passband channel spanning the frequency range 2.4-2.42 GHz. Assuming that we use64QAM signaling at 60 Mbits/s, choose a and b so that the pulse is Nyquist and exactly fills the channel bandwidth. (d) Sketch an argument showing that the magnitude of the transmitted waveform in the preceding settings is always finite.