[achairapart]

The DX7 was the first affordable, fully digital programmable keyboard to hit the market.

Also, technology for digital synthesis was already there, the big game was to avoid patent infringement from other companies.

For example, Casio invented the "Vowel–consonant synthesis" used in their 80s Casiotone keyboards mostly to prevent conflicts with an existing patent from Allen Organs[0]. And later, they came out with the "Phase Distortion Synthesis" as an *alternative* FM synthesis[1].

[0]: See the bottom of this page: http://weltenschule.de/TableHooters/Casio_CT-410V.html

[1]: https://electricdruid.net/phase-distortion-synthesis/