Ignoring the obvious
Not having a degree, I learned how to judge my "degree" level by what people with degrees said in times of trouble. I was often brought in to look at the most difficult problems, and like Dr. House's Baraku I very often was able to solve the problem when no one else could, despite being surrounded by guys with advanced degrees in electronics. I solved a lot of problems over the years, and thus, I never went without a job. As long as I wanted to work, I could find a job.
My buddy Terry brought me over to Maxim in 2006, and I did some awesome stuff over there. Terry had an MSEE, but he was crazy about me because I had a complete lock on mixed signal, he knew very well that I was the only expert on mixed signal he could find in the Portland area. One day Terry asked me to help him look at a problem he was having. We used a spectrum analyzer to look at the output of the chip in question and I saw this crazy humping pattern and exclaimed "What the hell is that?" Terry replied, "Oh it's just some artifacts." Looking at the pattern (as in the graphic above) I thought to myself, no, that's not some artifact, that is mathematical, something is going on there! Sure enough, I was right, and he was wrong, but it took me 8 years of dwelling on it to understand why we were seeing this crazy humping pattern on the spectrum analyzer.
I saw it again when I was playing with the Applicos ATX7006. Something mathematical was causing those humping patterns, but no reference anywhere seemed to explain it. Instead the web, and the library where I volunteered were full of completely insane theories about harmonic distortion. Did you know that vacuum tubes create only even harmonics? Neither did I (and it's not true). Did you know that symmetrical distortion causes odd harmonics? Audio Precision put out that howler, and I proved it wrong. When Audio Precision is wrong, you know that nobody out there understands what's going on. I've always found it most productive to go after things that other people don't understand. And boy this had all the makings of a gold mine, if only I could solve it.
With a lot of work, thinking, experimenting and perseverance, I solved it. Those humps are easy to explain. And it's funny; when I was writing Distortion, I nearly gave up on solving it. I mean, I had everything else solved, the fact that the harmonics are proportional to the area of the distortion, the difference between clipping and zero crossing distortion spectra, square wave and triangle wave spectra explained in every detail, everything, but that one thing. I even wrote a line apologizing for not being able to solve those humpy patterns. And then I had an epiphany, and as they say, the rest is history.
I'm not going to tell you what it is here (although I left you a hint), you have to have some reason to buy the book, but I will tell you this. Based on what Terry, Audio Precision, and Bruce say about harmonics, my educational level is much higher than a Master's degree. Just call me Doctor Dan, a Baraku.