@attie Apology accepted!

My interpretation of the bottom-left graph is that it is a plot of The Thing's resonant frequency. I agree that it could be clearer.

Yeah, the way they connect the dots from The Thing to contactless credit cards is questionable, but The Thing is certainly the earliest example of an intentional RF retroreflector.

@attie You piqued my interest, so I just watched the video, and I think they (appropriately) described the signal reflecting from The Thing purely as AM. The mechanism for producing AM is that the device's resonant frequency changes with air pressure, but the effect this has on the radio wave is AM.

I believe that the "parasitic frequency modulation" mentioned in Wikipedia is inconsequential. I don't see a citation.

@whitequark Bad books: The Dresden Files series follows a modern-day wizard/detective through various adventures. I found it good enough to be fun to read but bad enough that I wasn’t terribly invested.

Good DSP book: Practical Signal Processing by Mark Owen is my favorite introductory DSP book. It takes a conceptual approach and, I think, would make better bedtime reading than most texts on the subject.

Even with non-integer sample rates, the error of the old algorithm is less than the typical error of the internal crystal, but there are some specialized applications where the improvement could matter.

For example, HackRF One was used as a part of this time transfer system that achieved better than 40 ns precision: https://arxiv.org/abs/2406.13596

Clock generator precision was a significant limiting factor in this system, so I think that 256 times less error would result in a huge improvement overall.