1. Introduction to digital system control

The general structure of a closed-loop system, corrected using a digital computer, is shown in figure 1 .

—The analog-to-digital converter (ADC) converts the error ε (t ) between input and output into a digital value, and samples this error every T seconds.

—The digital computer reads the digital error value, stores it in memory and, using an algorithm, generates a digital control signal u (kT ).

—This signal is then transformed by a digital-to-analog converter (DAC) into a DC signal v (t ).

This signal v (t ) is usually amplified by a power amplifier and applied to the physical system to be controlled.

It should also be noted that the D/A converter must deliver...