Yeah, it doesn't even explain the image frequency problem in traditional superheterodyne receivers, which I'm sure is pretty fundamental to why I/Q exists. (Loo

Yeah, it doesn't even explain the image frequency problem in traditional superheterodyne receivers, which I'm sure is pretty fundamental to why I/Q exists. (Loosely speaking, a superheterodyne receiver transforms the input frequency to some fixed intermediate frequency by shifting everything by an adjustable local oscillator frequency. However, there are two different input frequencies that produce the same frequency on the output: one above the local oscillator by the same amount as that intermediate frequency, and one below it by the same amount. Those are basically the positive and negative frequencies the article talks about I/Q data being able to distinguish.)