Analog-to-Digital ConversionThe ana

Analog-to-Digital Conversion
The analog signals that come from sources
such as sensors and microphones are continuous. Their voltage value changes smoothly with
time. Another type of signal, called discrete,
can change in voltage value only at specified
points in time. A continuous signal must be
changed into a discrete signal to make it manageable for digital processing. The process of
changing a continuous signal involves sampling
it at points in time. Usually, a sample-andhold circuit is employed for the first part
of this process. In Figure 13-29(a) a continuous signal is shown, and in Figure 13-29(b), its discrete counterpart is shown. Sampling begins
at time t0.