Digital transmission
In digital transmission the continuous signal is first sampled by
slicing the signal at regular intervals into discrete values.
Signal samples are then quantified, their amplitudes are
approximated to the nearest pre-defined value.
Quantified samples are coded into binary words.
After this, the binary words are transmitted.
The length of a coded binary sample depends on that how
accurate the quantization must be.
For example, if the signals are presented with 256 different
(voltage) levels, the coded binary word is 8 bits long (28 = 256).