Microdigital were/are a Brazilian clone computer maker in a similar vein to Dick Smith in Australia. Aside from the copies of the Sinclair range of machines I know they also did TRS80 clones, hence the Midrodigital-badged VideoGenie I've got!
Here's a swift mail from Carlos Wilson:
" I also discover that the name TK came from the initials of the one of the founders of MICRODIGITAL (founded at 1981) the brothers George and Tomas Kovari."
TK90X - South American Spectrum 48K clone with joystick port. Came with switchable PSU, cables and spanish manual. Anyone read Spanish? :)