#6 in a series of articles about wander and jitter

So far, we’ve looked at what jitter is, and two ways of classifying it (The first way was by looking at whether it’s phase or amplitude jitter. The second way was to find out whether it is random or deterministic.) In this posting, we’ll talk about a different way of classifying jitter and wander – by the system that it’s affecting. Knowing this helps us in diagnosing where the jitter occurs in a system, since different systems exhibit different behaviours as a result of jitter.

We can put two major headings on the systems affected by jitter in your system:

• data jitter
• sampling jitter

If you have data jitter, then the timing errors in the carrier signal caused by the modulator cause the receiver device to make errors when it detects whether the carrier is a “high” or a “low” voltage.

If you have sampling jitter, then you’re measuring or playing the audio signal’s instantaneous level at the wrong time.

These two types of jitter will have different effects if they occur – so let’s look at them in the next two separate postings to keep things neat and tidy.