Phase Data: You’re not going to throw that away, are you? [Shop Talk: What You Didn’t Learn in School]

I hate to throw things out. Clinically, this is known as “hoarding disorder.” Sure, all of the piles of old newspapers in my house are starting to become a nuisance, but this affliction does have a benefit when it comes to distortion analysis. It turns out that the discarded phase information in FFTs—which you may never have even looked at—can be your best friend when tracking down harmonics. (See
Figure 1
.)