The $Z$-parameter matrix of a two port network relates the port voltages and port currents as follows:

$$ \left[\begin{array}{l} V_1 \\ V_2 \end{array}\right]=Z\left[\begin{array}{l} I_1 \\ I_2 \end{array}\right] $$

The Z-parameter matrix (with each entry in Ohms) of the network shown below is

___________.

Consider the discrete-time system below with input $x[n]$ and output $y[n]$. In the figure, $h_1[n]$ and $h_2[n]$ denote the impulse responses of LTI Subsystems 1 and 2, respectively. Also, $\delta[n]$ is the unit impulse, and $b>0$.

Assuming $h_2[n] \neq \delta[n]$, the overall system (denoted by the dashed box) is_________.

Consider a continuous-time, real-valued signal $f(t)$ whose Fourier transform $F(\omega)=$$\mathop f\limits_{ - \infty }^\infty $$ f(t) \exp (-j \omega t) d t$ exists.

Which one of the following statements is always TRUE?