Nyquist rate
The sampling rate for a signal must be at least twice the frequency of the highest frequency component of the signal.
Quantisation
The size of each zone / bucket / resolution of the quantised signal is (where n is the number of amplitude zones to divide the signal into):
\Delta = \frac{V_\t{max} - V_\t{min}}{n}
Exclusive of upper bound (and of V_\t{max} incidentally). For zones i \in [0, n), a given sample is within zone i if:
V_\t{min} + \Delta i \le v < V_\t{min} + \Delta (i+1)