Say the analog signal $x(t)$ and its spectrum $X_a(\Omega)$. After sampling with frequency $F_s$ or sampling period $T$ we get
$$x[n] \triangleq x(nT) = x\left(\frac{n}{F_s}\right)$$
and its spectrum $X_d(\omega)$.
The relationship between the two spectrums is
$$X_d(\omega) =\frac1T \sum ^{\infty}_{n=-\infty}X_a\left(\frac{\omega + 2\pi n}{T}\right)$$ $$\omega=T\Omega$$
For band-limited analog signal having spectrum in range $[-B,B]$. $X_a(\Omega)=0$ for $|\Omega| \geq B$ if $F_s$ is above Nyquist rate then $$X_d(\omega) =\frac1T X_a(\Omega)$$
For digital signal, its frequency is restrict in $[-\pi,\pi]$ but not the case of analog signal. The equation above means that $X_d(\omega)$ is not restricted in $[-\pi,\pi]$