For a $4$ASK $($Amplitude Shift Keying$)$ modulator with a carrier frequency of $700$ MHz and a bit rate of $1$ Mbps$,$ calculate:

$1.$ The number of bits per second.

$2.$ The minimum Nyquist bandwidth.

$3.$ The minimum bandwidth with a practical filter having a roll$-$off factor $(\backslash (\backslash$alpha $\backslash ))$ of $0\mathrm{.}3.$

$4.$ The theoretical and practical spectral efficiency.