The PSD and the power of a signal g(t) are, respectively, S_g($$\omega$$) and P_g. The PSD and the power of the signal ag(t) are, respectively

If a signal f(t) has energy E, the energy of the signal f(2t) is equal to

The region of convergence of the z- transform of a unit step function is

The transfer function of a system is given by $$H\left( s \right) = {1 \over {{s^2}\left( {s - 2} \right)}}$$. The impulse response of the system is