The purpose of a comb filter is to separate a composite video signal's luminance (Y) information from its color (C) information. There are several ways to perform Y/C separation and comb filters are the most common. There are different types of comb filters and they vary widely in performance. The differences are directly observable in the video artifacts that exist after separation. In this article I will explain what artifacts to expect form each type of Y/C separation filter and where to look for them. The best way to understand the advantages of the different comb filter technologies is to start with a little information about the composite video signal.