CHAPTER 10DISTORTIONS AND TEST SIGNALS
Distortion takes place whenever a signal passes through a circuit or piece of equipment that causes unwanted change to it. The action must not be confused with intentional alteration such as those for pictorial effect. This chapter deals with analogue and uses examples of composite video. Monitoring is usually composite, often of a temporary nature such as that for location work, and is therefore more prone to fault conditions.
We have already used the universal test signal, colour bars. The ramp is another useful test signal; it is easy to generate accurately and its form readily shows linearity changes. Both these test signals have limitations, and some of these have already been discussed.