3. Modeling disturbances

3.1 Origin of disturbances

Any electrical or electronic circuit is subject to the influence of disturbance signals that modify its behavior. These disruptive signals have different origins:

• they may appear in the circuit through electrical or magnetic coupling with another circuit;

• they may be due to the poor quality of the circuit's DC power supplies (presence of a residual AC signal superimposed on the DC signal);

• they come from the background noise generated by electronic components and resistors.