The DX7 patent is actually pretty good: https://patents.google.com/patent/US4554857A https://patents.google.com/patent/US4554857A It accurately describes the a

The DX7 patent is actually pretty good: https://patents.google.com/patent/US4554857A https://patents.google.com/patent/US4554857A It accurately describes the architecture of the DX7 and how it's implemented. There's a whole lot that it doesn't explain, but it was very helpful for understanding the chip. (I used a couple of diagrams from the patent in my article.)