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Understanding Anti-aliasing

Before I explain what anti-aliasing is, I'll cover aliasing. Of course, these two subjects are closely related. People almost never discuss aliasing, though.

Aliasing

Aliasing is what happens when analog data is represented on a digital system. A curved line drawn on a grid is a good example of analog data on a digital system (see Figure 42.22).

Figure 42.22. A line of grid representing analog data on a digital system.

When the analog data is converted to digital, some problems arise. The digital system in this example is the grid. To convert the analog line to a digital line, each point in the grid might represent ...