> I did a quick trawl through the patents filed by SiTimes, and I’m guessing the MEMS oscillator chip contains at least two separate oscillators. These oscillators are intentionally different, so that their frequency drift with temperature also have different, but predictable, curves. They can use the relative difference of the frequencies to very precisely measure the absolute temperature of the pair of oscillators by comparing the instantaneous difference between the two frequencies. In other words, they took the exact problem that plagues silicon designs, and turned it into a feature: they built a very precise temperature sensor out of two silicon oscillators.I finally got around to reading the excellent Logitude by Dava Sobel (https://www.goodreads.com/book/show/4806.Longitude) and to a lay-person this sounds like a similar principle that Harrison applied to design the bimetallic strip used to preserve the accuracy of his clocks in the face of temperature changes (https://en.wikipedia.org/wiki/Bimetallic_strip). Very cool.
civilized|4 years ago