¥ In an analog
signal, noise are added to the signal during transmission. The received signal will never be identical to the original signal.
¥ A digital signal will still be
subject to noise, but the difference between signal levels (an Ò0101Ó and an Ò0110Ó) will be sufficiently large so that the receiver can always determine the original signal level in each sampling period. The regenerated, so that the received digital data is an exact replica of the original digital data.
¥ Analog to digital conversion reduces the amount of information of the signal by approximating the analog signal with a digital signal. The
sampling period and number of levels of the digital signal should be selected in order to capture as much information of the original signal as possible